Open Marriages: Hollywood’s Worst Kept Secret?
Zac Efron and Vanessa Hudgens

Although the High School Musical couple didn’t make it to the end of the road together, it really isn’t all that shocking that the two kept loose tabs on one another. They may not exactly count as an open marriage per say, but the couple makes the list considering how outward they were about their possible future together.
Apparently Hudgens once revealed that Zac did not want to get married until he was 40 years old, but would request the ability to sleep with other women. Even worse, Efron made it clear that Vanessa would not have the same option during the marriage, so that was an easy choice for her to say goodbye.