What do I do?

This is crazy for me to actually speak about but I need opinions and thoughts from somebody looking from it on the outside. I met my boyfriend on a girls holiday, we had a long distant relationship for over a year and I decided to go and study in his town to be with him which is 200 miles away from my family, friends, my home. I went to study and I didn't enjoy it one bit as I spent my evenings and weekends with him or waiting for him to come home, I went home for a few weeks and met somebody who I just thought was amazing, I decided to leave my partner and move home to be with this 'amazing' man who let me wear what I wanted let me party, showed me off to everyone, however I got so sucked up in him I made some wrong decisions and left my dream job and brought me down I was always motivated and wanted to do well. However I decided my ex partner really did love me and I missed him. I then left my friends, family, job to go back to my holiday lover. However a few months after moving in together, he decided to stay out and go to the pub with the boys. This was while I was at home waiting for him, he would come home on cocaine and would lie about it. I have to pay half the bills even though he earns four times my wage. He never goes without drives a nice vehicle, tattoos, new clothes, nights out.. Etc. I've had to give up everything even having my nails done as I can't afford this. He started working with some older men who did a lot of cocaine and decided he would join them and start doing it at work, he would come home so drugged up but lied. He always claims his skint however he earns four times my wage and never goes without. I soon realised he was spending a lot more than I thought on cocaine. If I went out after work he would go mad at me!! I've not had a night out without him since I've moved in with him! The other weekend he went on a day sesh and call after call he was only an hour away but 12 hours later I knew he wasn't coming home. When he finally come home he went straight to the spare bed. I laid in bed and wound myself up even even more until I went into the bedroom screaming at home because he never shows me that he cares or loves me. He then decided he would start pushing me away from him, until I then punched him in the head. By this time he had left, the next day I woke up with bruises all over he had no mark. He told me last year he wanted to start trying for a baby howver since all this odd behaviour he now wants me back on contraception however I'm heartbroken he went on at me for ages for children I finally gave in and now he doesn't want them. What do I do?