Of course there are exceptions but generally speaking I don't do it. Over the last few years I advised friends on not meeting a S/O's child(ren).
My female friend was dating a dude with multiple kids (red flag). Anyway his youngest was like 3. I told her don't do it, its a bad idea but she insisted claiming that there's nothing wrong with meeting kids and how much she loves children (she got zero by the way). So they started hanging out on some family type shit, picnics, movies etc. I told her flat out "this nigga using his kid as an emotional anchor, when shit gets real he gonna pull the my 'daughter loves you' card". She didn't believe me, sure enough when homie started bullshitting and she cut him off he started that "my baby just want to say Hi, she misses you"...she was scarred, she's a nice chick so hurting the feelings of a small child isn't in her nature. Ultimately she caved and took him back, after awhile they broke up again and she changed her number. She called me weepy as fuck afterwards
My homie was trying to win over this chick (haven't known her that long) with like a 6yr old son. So this past Xmas he was talking about buying little man a Xmas gift, now I love kids and this is a good sentiment, but I told homie not to do it. I told him that shit is Pandora's Box or Hell's Gate. Once its open all the evil miasma within is gonna infect his pocketbook like nothing he's never seen before. Nigga aint listen to me though, bought the kid something (a movie or some shit) and now the bitch is asking him to pay for her son's haircuts and gym shoes....he opened the door for it and now the little nigga's daddy sitting back like:
I've only met the kids of friends, never of women I'm dating...I've always found it more responsible to NOT introduce people you just dating to your kids (I don't have any either) but some folks just don't agree.