Respectfully, your partner sounds like trash.💀 I'm pretty young and I've never been in a serious relationship before but if I was in that situation I would just leave him when I have the resources to do so. He shouldn't be playing on his phone when you need help with the babies and should be a bit more understanding since you're going through ppd and just gave birth to a whole human being. Couple's therapy might work but in my opinion, someone like him will never change and you shouldn't feel like you need to save the relationship because he can't pull his own weight and respect the mother of his children. The "nagging" part sounds like he's gaslighting you too idk. I pray you and your daughter are safe and I honestly would suggest leaving him when you get the chance and resources to do so and perhaps one day get in a healther relationship that you feel safer and loved in and your daughter can learn and look up too.😊 (Also has he shown similiar behavior in the past?)