What makes men do this to their sig other?

My husband and I have always had a rocky relationship since the 2nd year (we've been together 3 1/2 years and married almost a year with a son of one year) and we're almost complete opposites. I love him despite the differances and he said he loves me the same but I often told him that his actions spoke differant...He had an emotional affair for a month last year and that hurt me deeply. More so that he did it due to a false accusation that I was seeing another man but I wasn't. The guy was an old collegue from highschool and I've known him for 8 years and the friend had been enggaged for 3 years. I no longer talk to the friend because I was viewed as a threat to his relationship and the guy friend was a threat to my marriage so we quit talking 2 months ago. Now my husband has been suffering from depression and a weed addiction. We're currently getting counseling for all of this but after the counseling started it seems that he's gotten worse. I try to take him out more into the sunny outdoors and give him more affection but he just seems to keep his distance. He won't hug me unless its just before or during . He says "I'm not in the mood to be lovey" or affectionate. Before the couseling there was pushing and grabbing hard but that stopped after we found a good church and counseling and he was prescribed medication. He says that I'll never understand him whn I do try to listen and respond back but he gets defensive with nearly everything I say. He's also gotten ruder lately or meaner. He'll be really mean to me for no reason one minute(not abuse, just mean with his words)and the next he'll apologize. I tell him how attractive he is to me, cook for him, and do countless things for him but it seems he's never satisfied. I'm confused and about to seperate again. This is hard on me and I'm emotionally hurt. Whats going on?