I think that's probably the best thing to do. This guy is not going anywhere and your boyfriend is long distance. I know you've had him for years, but it could be it's run its course. You are obviously attracted to your friend.
Try not to dwell on the sadness of it. Think of it as an opportunity to explore something new with someone you have a lot of history and trust with.
I went home to him and we broke up. He's really sad. He still loves me. I still love him. But probably not in the same way as a month ago. He thinks I'm making a mistake, that I'm making this decision too quickly. But it's been a month since I first kissed my friend and it's been on my mind ever since. I didn't make the decision because I kissed him. I guess I kissed him because I'd already made the decision. It all sucks. I'm scared I've made the wrong decision, but I don't know what else to do. I'm just kinda scared and worried about everyone involved in this situation and I feel like it's my fault, even though I can't really do anything about.
I'm just hurting now and feel so bad that I had to do this to him.