It’s pretty normal in a relationship to talk about your past, including your past dating experiences. But it’s also important to note how long it’s been since your boyfriend broke up with his old girlfriend. If his last relationship was last than six months ago, he’s venting because he’s still healing from the hurt, says Cary McNeal for the “Guyspeak” column of "Glamour" magazine. If it has been a few years and he’s still angry at her -- or still seems to be in love with her -- that could be a red flag, McNeal notes.

How speedily he shares his old girlfriend stories with you is also an important factor to assess. His ex-girlfriend sob story is not an appropriate subject for the first date, says Salter. But, she writes, it’s natural for people to reveal more about their pasts as their relationships grow more intimate. If you just started dating this guy and every date is a saga about his old girlfriends, that’s a clue that he’s still stuck in the past. But if you’ve progressed to a point where you’re starting to share more with each other, then you’ll learn about the old girlfriends and move on, says Salter.

Beware, however, the guy who won’t stop talking about his crazy, psycho ex. Especially if he has more than one. The ex-girlfriend’s “crazy” actions rarely come out of nowhere; they’re usually prompted by poor treatment from the guy in question, says dating coach and author Matt Titus. A man calls his ex-girlfriend crazy because it makes him look like a victim and absolves him of any blame for what went south in the relationship, says Titus. “Believe half of what you hear and all of what you see,” he advises. Your boyfriend may treat you with care and concern, or he may have a pattern of blowing women off and then blaming them for their reactions.

It’s fine to talk about your pasts, but don’t fall into the trap of comparing yourself to his old girlfriends, cautions Salter. And certainly don’t let him compare you to them. If you find yourself “walking on eggshells” because you’re afraid to drive him nuts by doing something his old girlfriend did, reflect on why you feel so nervous. You should be able to focus on your present relationship and be yourself around him.