Alorna, Just wanted to add that I hope you're taking care of yourself. You've probably heard the example of how airline passengers with young children are told to put on their own oxygen masks first before trying to put them on their children in case of an emergency.
Make sure that you don't become isolated. Surround yourself with supportive friends and family. Look for support groups (perhaps through a women's shelter, church, or 12 step group). If you don't know where to start looking, try calling your local domestic violence shelter or hotline or your local family services agency. You're strong, and you'll probably learn in the next few months that you're stronger than you ever imagined you could be especially with a baby to protect and care for. I don't know if you work outside the home or not but you may want to improve or maintain your job skills so that you don't feel trapped. He'll do everything he can to deny that he has a problem and will try to blame it on you.
And, if you decide to leave him, please be very, very careful and have somebody with you (and don't get into an argument or fight with him). Some men become physically abusive for the first time when their wives leave.
Even if you're on the right track, you'll get run over if you just sit there. Will Rogers
To love at all is to be vulnerable. Love anything, and your heart will certainly be wrung and possibly be broken. C. S. Lewis