What should I do about my fiances anger problems?

We have been dating for about 3 1/2 years now... we just got engaged a little while ago. I love him more than anything but I just don't know what to do about his temper. Leaving him is not an option. I just want to know what I should do to help with his temper problems. If something doesn't go right for him he flips out and screams at me. He throws things and hits things and sometimes he'll raise his fist at me. He's never hit me before. He has bitten me, and pushed me but never hit me. ( He and my sister got into an argument in the parking lot and I put my hand across his mouth to keep him from yelling at her.) We can't afford anger management classes right now. Although he has already gone threw anger management when he was younger and it obviously didn't work. I feel like I have to walk on eggshells with what I say and how I say it. He and his mom get into arguments super bad way too often. They yell and cuss each other out. I just don't know what to do anymore. If I say that I'm going to leave as in go for a car ride to get away from the situation, he'll flip out worse and threaten to kill himself or break things.He's gotten better than before because I made him do some anger management online things. They were free but he didn't do them very long and got aggravated after a while. I need advise on how I should handle this. I know that I don't make situations better sometimes but I don't start off yelling at him. After a while I start to yell back because I can't stand it. He also complains and whines about everything. What can I do? He is extremely negative about everything!!!!