In the past, the idea of being in an open relationship would have been intolerable to most couples, unless you happened to live in one of the more liberal hippie communities of the 1970s.

Currently however, research has shown that societal attitudes to open relationships, as well as relationships that are openly polyamorous are changing, with more people accepting that they are a bona fide option for some couples, even if they don’t want to engage in such relationships.

To bolster these reports, there was a survey in May 2015, of over 2000 Americans, on their attitudes towards open relationships. A surprising 45% of those questioned said they wouldn’t automatically leave their partners, in the event that they proposed an open relationship.

While attitudes may be more relaxed, however, this hasn’t yet translated to a significant number of people who admit to being in an open relationship themselves. The same survey actually showed that only 4% of all Americans consider themselves to be in an open relationship.

Interestingly, those living in the West Coast of the USA were much more relaxed about open relationships, with 24% saying that they were not morally opposed to the concept. This could go some way towards explaining why so many Hollywood celebrities are in open relationships.

So, check out the list below of celebrities who have admitted to be, or are rumoured to be, in open relationships. Are you surprised by any of them?

15. Dolly Parton

She’s a country music singer, actress, businesswoman, and icon. There is nothing that Dolly Parton can’t do. That includes making her marriage work for over 50 years, despite the unconventional arrangement she has with her husband, Carl Dean. The pair married in 1966, and recently renewed their vows, so their open relationship must be working out well, even though there are rumors that it is Dolly who pushed for the open status, rather than her husband. Dolly has been honest that men are her “weakness,” and the pair have an arrangement that if one of them does end up cheating, then they just won’t tell the other person about it.

14. Gwen Stefani and Gavin Rossdale

Before rock music’s hottest couple split in 2015 after 13 years of marriage, there were rumors that the couple enjoyed an open relationship. Although there were also rumors that this was an arrangement that only Rossdale took advantage of – something which seems to have been borne out by the fact that gossip magazines blamed the couple’s divorce on Rossdale’s affair with the nanny. Well, only Gavin and Gwen know the real truth, but it does seem that “open relationship” rumors attach themselves to lots of celebrity couples who spend a lot of time apart. I mean they do tend to have very hectic schedules.

13. Ethan Hawke

Actor Ethan Hawke was another celebrity husband who followed the well-worn route of cheating with the nanny. Because of this scandal he and his then wife Uma Thurman divorced in 2005. Hawke did at least go on to marry the nanny in question, Ryan Shawhughes. Reports are that Hawke and his new wife enjoy an open relationship, with the Training Day actor saying that sexual fidelity shouldn’t be something you base your entire relationship on. However, it’s unclear whether Shawhughes has much say about their open relationship status. This could simply be a case of Hawke finding a woman who is, so far, willing to let him have his cake and eat it.

12. Demi Moore and Ashton Kutcher

When news first broke about Moore and Kutcher’s relationship, no-one gave their marriage much of a chance, mainly because of the significant age difference between the two. However, it turns out that the couple had an unusual way of keeping their marriage alive, in the bedroom at least. According to gossip magazines, Demi and Ashton would often invite other women into their bed in a bid to spice things up and keep them both interested. The problems only started occurring when Kutcher took this openness a step too far, and started to see other women when his wife wasn’t around to supervise, leading to the couple’s divorce in 2013.

11. T-Pain

Rapper T-Pain and his wife Amber Najm have a similar set up to Demi and Ashton, with both being allowed to entertain other women, so long as their partner is there to supervise or even join in. Unfortunately, T-Pain, just like Ashton, seems to have taken his “free pass” a little too far, and has admitted to cheating on his wife outside the terms of their open relationship. Mrs. T-Pain has been a little more forgiving than Demi Moore, and despite her husband’s infidelities the couple is still happily married, so far.

10. Mo’Nique

When is an open relationship simply a justification for one partner to cheat with impunity? Actress and comedian Mo’Nique might well know the answer to that one. She has often described her relationship with husband, Sidney Hicks, as “open”, despite the fact that she chooses to be faithful to him completely, while allowing him to have flings and affairs with other women. Perhaps Mo’Nique is genuinely happy with their arrangement, but it would be interesting to see what her husband’s reaction would be if she ever decided to take advantage of their open relationship status.

9. Megan Fox and Brian Austin Green

Actors Megan Fox and Brian Austin Green also practiced a one-sided open relationship, although in their case, it was the wife who wanted the freedom to have a fling now and then, rather than the husband. Apparently, the couple made the decision to allow Fox to “explore her feelings” for other people, while she made up her mind about whether or not she wanted to commit to the relationship before their 2010 wedding. There were rumors that they stuck to the arrangement, and that it might even have contributed to the couple’s eventual split, five years later.

8. Larry King

Political journalist and TV presenter, Larry King, is probably one of the last people you would expect to be in an open relationship. Yet according to his sixth wife, Julie Alexander, King enjoyed an open relationship with his seventh wife, Shawn Southwick, who he married in 1997. What followed that is Southwick reportedly had a long-term affair with the baseball coach King hired for their two young sons, while King himself was rumored to have had a fling with his wife’s sister! Eventually, all this openness took a toll on the relationship, and the couple divorced in 2010, though they are now attempting to reconcile.

7. Pink

Singer Pink and motocross rider, Carey Hart, married in 2006, and have had a famously tempestuous relationship ever since, separating in 2008 before getting back together, and welcoming their first child in 2011. Before their split, the couple enjoyed what some have described as a “don’t ask, don’t tell” policy within their marriage, accepting that both were likely to stray because of their busy and very separate lifestyles. Pink reportedly put her foot down when her husband was seen out and about with the same mystery blonde night after night. Gossip magazines now report that since reconciling, the couple no longer has an open relationship.

6. Justin Timberlake and Jessica Biel

Although Justin Timberlake and Jessica Biel are now very “exclusive,” in the early days of their relationship, there were rumors that they took a more relaxed approach to fidelity. The gossip columnists even suggested that Justin and Jess were little more than friends with benefits after their premature split in 2009. However, the more likely truth is that Timberlake wasn’t ready to settle down, having just emerged from a serious long-term relationship. Jess was willing to give her man a little time and space, knowing that he would come around in the end. And why wouldn’t he, when he had Jessica Biel wait patiently for him?

5. Newt Gingrich

Politicians and open relationships do not mix well, even if both parties agree to the open relationship status, simply because it is difficult for voters to accept this alternative lifestyle, especially in the US. Newt Gingrich reportedly asked his ex-wife for an open relationship, something which the Georgia Republican angrily denied, all while admitting that he had, nevertheless, enjoyed a six-year affair with a Washington staffer. Judging by the public reaction to the two scandals, it seems that Americans hate it when their elected leaders engage in open relationships. On the contrary though, other countries have a very different attitude to the private lives of their politicians. In France, for example, former President Francois Mitterrand, openly visited his mistress of 32-years in her home near the Presidential palace, and even fathered a daughter with her, during his successful political career.

4. Hugh Hefner

It would be reasonable to question whether Hugh Hefner, creator of the Playboy empire, has ever been involved in a committed relationship, let alone enjoyed an open one. Hefner is famous not just for his business acumen, and the legendary parties at his Playboy Mansion, but also his numerous relationships with blonde, nubile Playboy bunnies, many of whom are half his age or even less. He has had short-lived marriages to two of his bunnies – Kimberley Conrad who was 36 years his junior, and Crystal Harris, who was 60 years younger than Hefner when they married. Perhaps open relationships are good for your health, considering that Hefner is still partying well into his 90s.

3. Brangelina

The dream may have come to an end with the news that Brad Pitt and Angelina Jolie are splitting up after 12 years together, and just two years after they got married. Perhaps, the warning signs were there all along in the couple’s rather cavalier attitude towards fidelity. Jolie admitted in interviews prior to their marriage that she didn’t see fidelity as “essential” in a relationship, and that being married was not about being “chained together” or even living together. A mature attitude towards modern marriage, perhaps, but it doesn’t seem to have done the couple much good in the long-run.

2. Will Smith and Jada Pinkett

Jada Pinkett-Smith has often spoken about the open nature of her relationship and marriage with actor, Will Smith. The pair, who have been married since 1998, have been plagued by rumors of affairs, flings and separations, but Jada has always been clear that her husband is his own man, saying that Will can do whatever he likes, as long he can “look himself in the mirror.” While some have suggested that this is a tacit admission that the couple have an open relationship, it could just as easily be seen as a warning to Will, should he ever decide to stray again.

1. Tilda Swinton

Some celebrity couples may play at having an open relationship, but actress Tilda Swinton and her artist partner John Byrne, had a go at the real thing. While Tilda was in a long-term relationship with Byrne, she was also regularly seen out and about with a young artist called Sandro Kopp. Tilda would then take Kopp home to the house in Scotland she shared with Byrne, where the three of them would stay under the same roof, although it was never clear what the sleeping arrangements were. However, even this very mature and adult attitude to open relationships could only go so far, and Byrne and the Chronicles of Narnia actress split soon afterwards, though Kopp is still very much on the scene. Whether Kopp and Swinton also enjoy an open relationship has not yet been revealed.

Sources: tandfonline.com, dailymail.co.uk, madamenoire.com, usmagazine.com, nytimes.com