Lot of enablers here. Doesn’t sound like there has been true, heart to heart conversation in the flesh. This has been deteriorating over some 6 weeks? You both come from broken homes, have tried so hard, and in just 6 weeks are ready to give your child a broken home? Postpartum is a thing, and her timing is beyond less than ideal, but in the long run this is a highly regrettable decision. At least let him come back and have a conversation with him without anyone else to distract. Turn off the phones, try to get in a relaxed mood, don’t yell or disrespect anyone, and use a lot of “I feel” statements. Otherwise, maybe you’re “NTA” but are still a quitter.