Guy friend / boyfriend issues

This is a longer post, as there's a bit to explain, but it's an issue that has really been bothering me for a couple of months. I would most appreciate feedback in any way When I moved to my current home two years ago, there was a guy a year older than I at my school that I had an insane crush on but being the way I was, we only spoke a few times. After a year, we got closer and hooked-up(make-out kind) at the end of Summer before he headed off to college. Even after, we became good friends and talk on a regular basis. I now have a loving boyfriend but he lives across the country which causes problems, on top of some personal matters that have been a real problem as of late. He take antidepressants but between doses, he will get really angry and act very selfish, saying things that are downright nasty and disrespectful. It's happened so often, what he says no longer hurts and I just don't want to talk to him because I don't want to risk having to endue one of these time-wasting, energy-consuming fits. After he takes his medication, the dosage of which has been 'fixed' several times, he is extremely sorry and apologetic and goes back to who I fell in love with. I only see him every couple of months and, starting this summer, he's going to be living in my state and city. The college friend I mentioned above is now home for a while before heading off to work. Since he's a good friend of mine and I was frustrated, emotionally and sexually, we ended up sleeping together. We retained contact and didn't act any different. We slept together a second time and, I remember reading that a general rule is that you don't kiss, cuddle, or generally act touchy-feely after that kind of encounter, but we did all three. It was a nice feeling, with no feelings of guilt of what I had done. He was courteous, sensitive, and the sex was the best I'd ever had(out of two total people, him and my boyfriend). With my boyfriend, along with being quite well-endowed while I am a much smaller individual, he has more experience and it's all about what he knows and wants during sex, with no regard to my feelings or the pain I feel consistently. He apologizes afterward when, every time, I bleed. And that's it. I asked my friend what he thought of me because of all this and he is attracted to me and thinks I'm a really nice, unique, sweet individual. I also asked if he's ever consider dating me and he wasn't sure. He's a normally standoffish guy and he's nice, but extra attentive and nice to me in any situation. Now, I really like my friend and, though my boyfriend says he'll fix what he's doing, I doubt that claim as he's made it in the past. What would you do in this situation? What would you recommend I do? What is my friend feeling if he's being so friendly and kind to me? Should I break up with my boyfriend?