Gosh, what a can of worms......
I was a single mother of a toddler when I met my ex DH and we were married for 14 years before his utter twattishness ended things. Don't shoot me, but when I met him in my late 20s he was so very lovely to me and helped me sort out my life after a huge amount of trauma and he was a great SD to my DS........ and the huge red flag that he had three ex wives and five daughters (yep, I was completely naive) didn't bother me - the older girls loved out of area (and it was all very complicated) and the two younger became a part of our lives - when they were in their exam years their Mum moved to be with her new partner so they moved in with us to complete their education. So I've done the blended family thing and yes, it was challenging and complicated. But it was just our lives, we made it mainly work. Ex DH was in turn a great father and a shit one, depending.
New DP I met at 42, he was the same age. My DS was still living with exDH as he made that choice so I was now essentially child free to an extent. DP had never had kids but had been married and had a couple of LTRs. He had never wanted children - was absolutely upfront about his fear he'd make a terrible father because he wanted a spontaneous lifestyle. He's been mainly great with DS who has lived independently and with us at various times, but he didn't have to parent him as such. I respect his outlook and give him kudos for not being rail-roaded into anything that would have lead to potential kids feeling in any way not his priority.
When we got together I lost count of the number of people who asked if we were going to have offspring - which would leave us both reacting in mock horror. Having my DS is wonderful, but repeating the process all over again at 42 just did not appeal.
I guess what I'm saying is horses for courses. I wasn't looking for any man - the one I ended up with was a wonderful bonus. I think if I'd met someone with children who was "ideal" I would have been open to making it work, but having dealt with all my exDH's "baggage" it would have been a slow and carefully negotiated process because I do think children take priority in these situations.
I've never been a planner as such, because life has often stuck two fingers up at my attempts so I try to adapt to the moment.
I've learned alot through my life, and the biggest lesson is that while it's great to have a broad idea of what might be ideal, if one isn't somewhat flexible, you can miss out on things that actually are quite positive and enriching.
Oh, and everyone is different - generalising is one of the biggest mistakes in my opinion.