It sounds like NRE making you overthink things. Oxytocin and endorphins have your head spinning about the ideal mate, nesting, and raising babies! Relax and see how your relationships go first. Focus on the here and now. The thing is, you could have two relationships here that are absolutely wonderful for you, emotionally, psychologically, intellectually, and sexually. Having children is something you can think about once both relationships are solid, grounded, and more committed. I think you're putting the cart before the horse, and I would table any discussion of childrearing for now, if I were you.
The world opens up... when you do.
"Oh, oh, can't you see? Love is the drug for me." ~Bryan Ferry
"Love and the self are one . . ." ~Leo Buscaglia "