I need advice

my boyfriend & I have been dating for like 3 years now. we're both juniors. we've known eachother since like 7th grade. I made the most horrible mistake I could have. I cheated on him last january. i sentnit was terrible & I hated myself for it. i know thats sometning you cant do then say you're sorry & everything be okay but it's been so bad. we broke up for maybe 2 months. then we got back together wanting to repair the relationship. it was really hard. really really hard. not to mention I moved from arizona (where he is) to texas (where I am now) in late december. it only made matters worse that we were so far away. I miss him so much and we rarely get into fights besides when he gets into a funk & remembers what I did. I can't blame him. anyone would do that. he doesn't really.trust me. & soon well be going to college. I'm moving home. to be with him id love it, but regardless I'll be going home. a couple of days ago we took a bad turn & have been fighting nonstop about it. he just doesn't trust me & now he thinks I'm trying to get with his best friend. I'm not. I don't know how to make things better. everyone says there is no way but there has to be some way. I just want him to trust me, or want to trust me. it's been really hard. any advice