The biggest risk you've taken for love

The parents of one of my friends have a cute story about how they met. I heard the story years ago, so forgive me if my memory is a little foggy. But the gist of the story is this.

The pair was in gym class together in high school, and at the time my friend's mom was engaged to another man. I believe they were set to marry right after graduation. One day, my friend's dad approaches her and tells her that he could treat her better than her fiance ever could, if she would just give him a chance. She broke off the engagement. Not long after, my friend's parents married.

Asking out an already engaged woman was a gutsy move for my friend's dad, and it was a risky move for my friend's mom to accept. If I were already engaged to someone, I don't think I could even consider giving up the plans there already were in place for myself. If the new relationship didn't work out, my friend's mom also would have lost her old love. But sometimes, as in this case, taking a single risk produces a great reward. The couple has been married for around 25 years now, I believe.

What's the biggest risk you have ever taken for love? Have you ever gone after someone who was already taken? Has anyone approached you about leaving your current SO for them?