Pregnant and S/O is NOT being so nice at all..?

Before I got pregnant me and my fiance had the BEST relationship. He was very sweet and very attentive to my needs. I found out I was pregnant July 20, 2009 and we were both VERY excited. I will be 30 weeks pregnant on January 17th and ever since my 10th week of pregnancy my fiance has been NOTHING BUT a JERK! He plays his video game from the time he gets home from work (3.45) to the time he goes to sleep (10.30). I cook, clean, do laundry and take care of everything in our home. He has become EXTREMELY LAZY and just wants to drink and play his Call of Duty video game! He's rude, disrespectful, doesn't listen to a word I say to him, he doesn't ever want to talk and he will not have with me. I don't believe he is cheating on me considering I'm with him 24/7 except for the time he's at work. My whole family keeps telling me to leave him, but I just have this feeling that once our son Jasper is born that things will get better. I've freaked out on him many times before and have threatened him about me moving out. He honestly doesn't seem to care and that bothers me. I have never loved anyone so much in my life and if I would've known he was going to treat me this way when I'm pregnant I would've left him a very long time ago. Stress and depression have totally taken over my body which makes me worry about my unborn son. When we are around people he treats me like a Queen, but then when it's just me and him he is unbelievably rude and disrespectful to me. We fight almost everyday because of his attitude. He rubs it in my face that he brings in the money and that I don't work. My tummy is quite big now and I can't do as much as I used to. He expects me to lift things still and to do normal everyday activities for a non pregnant woman. I don't know what happened to him? It honestly breaks my heart to know that I've let a man ruin my life. I'm always upset and I've already started having contractions (I'm only 29 weeks). I don't want to have a premature birth and I want my son to be healthy, I just feel that if I leave him I will be 100x more depressed and stressed about not having him. I've talked to him many times about how I feel and nothing seems to work. I miss my fiances love and I'm just wondering what I can do to get it back...Please help me!