Have you ever reached the point in your relationship where it feels like the only thing that will save it is a strict ultimatum? For some couples, an "or else" is an immediate deal breaker, but for others, it can actually change things for the better.

Here are 17 celebs who gave their partner an ultimatum — and how it worked out for them:

1.

THE ULTIMATUM: After separating from his first wife, Diandra Luker, Michael Douglas began seeing not one, not two, but five women. In his memoir, One Helluva Ride , he wrote , "I made sure they all lived in different cities, which felt like a respectful way to be non-monogamous. ... None of them asked for a commitment or even asked what else I was up to. I am sure they were seeing other people, too." However, everything changed when he met Catherine Zeta-Jones.

In 1998, Michael and Catherine crossed paths at the Deauville Film Festival. Initially, he struck out, but then he sent flowers to the small Scottish island where she was filming a movie.…