Relationship changed after baby

My fiancé has changed so much since having the baby. Before our son was born, we were on a high and everything was alright. Then in the hospital the days after he was born, things started to fall apart between us. In the hospital while I recovered from my c section, he barely helped me. Then the following weeks, our relationship got worse. At first we argued over my fiancé’s lack of properly caring for the baby. He did try but sometimes I felt like he was doing the bare minimum. Then we argued over having to live with his in laws as I was struggling to get comfortable living with them. Then we stayed with my mom for a bit and it turned into him thinking I hate his family because I feel more comfortable being at my moms. We argue every day and I try to tell him we need to stop but he’ll get triggered if I say something and then it starts again.

I just miss how we used to be before the baby. I love my baby so much but sometimes I feel like he’s reason we don’t get along anymore. I feel like we were so excited for this part of our lives and once it got here, everything fell apart.

I cry everyday because I want to have a good relationship with my fiancé so our baby can have a good family but I just feel so under appreciated and lonely.

I had a best friend in my fiancé before the baby and now it’s always us vs something.

Does it get better? I really feel so down that I’m losing romantic interest in my fiancé and I honestly feel like he’s a stranger that I’m raising a baby with right now. Before we were in sync and best friends and now I don’t know what to do anymore.