I agree with Spring Haze about the seeking of treatment. PPD can be very severe, and if you really think that is what acted as a catalyst for the fights, then him seeing you take ownership of that and try to correct it will mean a lot. Plus, you say you realize that it is not okay to hit someone, but I am sure you knew that before as well. It isn't a new thought, which I am sure he understands too.
His comment about you meeting someone last night sounds like he is sort of hurt and confused by you as well. It has only been a week and you are asking him to tell you definitively if you should move on? Especially after you two talked for a long time and had good conversations the day before when you were asking if there is a chance for the two of you? That would confuse most people, I think. So he probably said one of the first things that popped into his mind, not because he is trying to hurt you, but because he is hurting.
Slow down. Give it time. Take care of yourself. Take care of your child. If he wants to be a good father to his child, he will be around. No need to break the world records for ending and getting over a relationship.
Good luck.
Brought to you by Dating With Devon!