Why did he change so much after marriage?(long story)

Well, my husband and I got married January 3,2015 after being together since September 2007. He was always a good man and very supportive and loving. We decided to have a baby 2011 (born in 2012). He was so helpful and loved our son so dearly. He got a job to support us financially and always showed how much he loves us. We were sooo happy! In 2013 he proposed to me and told me I'm his other half. We finally tied the knot this year because we knew we were meant for eachother. Well, after we got married he completely changed. He didn't want sex anymore. He couldn't get enough of me before marriage then all of a sudden after marriage he has absolutely no sex drive. Then he texts me 2 weeks ago while he's at work telling me he quit his job and that he doesn't care anymore and says he's never going to support me and my son financially and that his last paycheck will all go to him. After that he came home took some of his stuff and leaves! Just leaves with no explanation! Idk what his problem is but we haven't seen or spoke to each other since then. He left town and just ditched me and now I have no way to support my son because I don't have a job. I love my husband so much and I'm just breaking apart. Idk what to do IF he does come back. should I take him back if he does come or just hurt him and ignore him like he's hurting me now. It sucks being completely ignored by my own new husband I just recently married! BTW, he's a Marijuana addict who has been trying to quit since our son was born but every few weeks he goes back to smoking it.