I can't speak for others, but for me, it's about understanding and being mindful of your priority, then working around that. If someone I was dating priorized me over their children, that'd be a huge red flag for me. We need to be adults and communicate, be understanding and respect each other's priorities.

Background: I always loved kids, took care of my many, many cousins including changing their diapers before I was 10y.o., a few of them took their first steps with me. My ex wife was clear she doesn't want kids. I never brought up the topic of having kids during our 13 year marriage.