9 Relationship Regrets: “I should have been more cool and collected.”

7. You dated a man who was already in a relationship.

“This is so cliché, but I thought I was different. I thought he would leave his girlfriend for me, but he never did.” The most important rule to remember: Never date a man who is married or who has a girlfriend. There is no happy ending in these situations. Before you commit yourself, check his past relationships—make sure things are completely over and there are no secrets.