Could some man please explain this to me?

I occasionally go on dates hoping for the best. What I have found most often is that the man waits until he feels a little bit comfortable the first time we meet in person and then spends time complaining about his ex.

On my most recent date, we spoke on the phone beforehand and he mentioned how women do this and how much he dislikes it. I started laughing and said I agree let’s just try and have a good time since venting about exes on a first date feels negative and counterintuitive. He agreed. However, on our first meeting, after about 30 minutes, he started complaining about his ex-wife and how much money he lost in his divorce.

Why does this keep happening? On a first couple of dates I just want to laugh, get to know the person, and hopefully have fun. Don’t men want this as well?