hurt and confused

Hi ladies! I've been having a really tough time lately and I'm hoping someone on here will be able to give helpful advice and understand what I'm saying.
I am a sexual assault survivor. It was about 6 years ago with someone I was very close to. Luckily, I was able to get out and file a report immediately and legally everything was taken care of. I still get flashbacks now and then and get really anxious sometimes when having sex with my boyfriend (we've been together almost 4 years). 
Today we were kind of getting in the mood and he didn't understand why I wanted-- needed-- to stop. He doesnt understand the pain that the sexual assault caused me all those years ago. The worst part about everything is that he yelled, slammed doors, called me a coward (and more). 
As I'm writing this I'm balling my eyes out. I do everything for this guy who "loves me so badly" but as soon as I have any emotion it's like I have to hold back unless I want to be screamed at. 
I don't think I'm a bad person, I've just gone through a lot. 
Any kind words would be greatly appreciated.