I feel for you, it can be so tough when you can see what you are doing to your relationship and yet feel powerless to hold it together. I know when I am hurting I tend to hurt others both intentionally (as a cry for help) and unintentionally as I struggle through the day. Communication can be a really effective tool. Try to tell your partner every day how much they mean to you, how much you appreciate their support and love, and how it is not their fault for the way you are feeling. And let them know how much you are trying. You could also tell your Pdoc how you are going and see if there is anything they can do to help. Are you continuing drug free Therapy? Do what you can, Then give yourself some time.

Being a bloke I have never had a baby, but I can imagine that Bipolar and recently giving birth would put an awful lot of hormones out of balance all at the same time. It's not always going to be like it is now. Things will settle down. You will stabilize. Then you can start to really enjoy that beautiful baby and the new family that you have created.

I wish you the very best for you and your family