Adviceeeee plssss

I usually don’t ask for advice regarding relationships but I’ve never been in a situation like this before, I bet a guy we’ve been talking and we’ve gotten a long pretty well only thing is that he has a daughter from his past relationship. I’ve never been or talked with someone that has kids , at first I thought we were just getting along since we’re still getting to know each other and it wouldn’t be anything serious but he seems to actually want a serious relationship with me he’s mentioned it a few times , I know that he does see his daughter and does provide for her financially but I want to know what happened with that relationship and why it didn’t work out I just don’t know how to bring up the topic . Has anyone been in a similar situation? If so how did things work out for you guys ?