there doesnt have to be any drama. sounds like they are both well over each other. Im assuming if they are both mature then they will set up some kind of reasonable custody arrangement and he will just have to pay child support.
My ex and I have 2 kids together (ages 15 and 8) and we have been apart 5 years. he and i share custody of the kids but have nothing to do with each other, other than the occasional text. he and his gf have been together over 4 years and I haven't even met her. so just because he has to deal with his ex, doesnt mean that you will have anything to do with her.
Is his ex poly as well? will your new boyfriend be open with her about being poly? if he does decide he wants to get back together with her, will you still be in the picture?
As a mother of a small baby right now, there is no way I would allow anyone to take her for more than a few hours, esp if she's breastfeeding. i would think his time with the baby at this point would be very limited unless she's not the attached type. some moms just want to hand the kid off so they can do their own thing.
Sue, in a vee with my polysexual husband Nate and my mono boyfriend Sam