husbands after birth

Abby
Before I got pregnant my husband was the most loving, most supportive, most amazing guy ever. My knight in shining armor, the love of my life, my home. We both wanted a baby to complete our family and bring more love into our lives. While I was pregnant he was amazing, cared for me, helped me, did all the cooking and cleaning, loved me so much. As soon as I had our daughter, even in the hospital, it's like a switch flipped. He has been depressed, says he's so unhappy, and doesn't help take care of her at all. It's been an adjustment for me being a mom, and I do everything for her. I breast feed so I'm always the one to feed her and ger up w her at night. He can't handle her crying so I'm always the one to hold and comfort her. I've done my best to keep him happy too, (tmi) we have sex at least 3 times a week even though I'm exhausted, I tiptoe around his feelings all the time. All he does is go to the gym, go to school, come home and sit on the couch. And he claims to be tired and unhappy and says that I'm miserable to be around (I'm not, I put on a happy face for him every single day). He's left twice but came back apologetic both times. Now he tells me he wants a divorce, our daughter that we both wanted so desperately is 3 months old. Why are some men such assholes after babies are born???? I don't regret my daughter, she is amazing, the biggest blessing in my life. But I am starting to regret her father. When is it time to accept defeat and give up on my marriage? I meant my vows and am willing to fight for my family. But when is enough enough?