Ashton Kutcher and Mila Kunis

Finding out your ex has moved on with someone else is bad enough, but imagine how Demi Moore felt when she found out her ex, Ashton Kutcher , was dating old friend and That 70s Show co-star Mila Kunis, who is two decades younger. Ouch!

"She is beyond heartbroken," a source told RadarOnline. "Even though Ashton cheated on her all the time, it was with random girls, it wasn't a relationship like it is with Mila and that is what is killing Demi now."

It looks like Ashton's traded her in for a younger model. Scroll through to see other stars that have done the same!