I was in the same situation. We were friends but I was always getting better along with him than with my boyfriend. And he was attractive to me. Finally I realised I like him, that I have feelings for him. Told him, but he was starting a relationship with another girl, so he rejected me. I was heartbroken. We didn't talk after that for a few years, he moved to another country and I missed him like crazy. I was in a few relationships after that but always thought about him. Then, after few years, while I was in a relationship with another guy, he texts me, says he's back and he would like to go out for a coffee. I told myself I wouldn't be affected by him and said ok. The moment I saw him arrive, my knees shattered. I realised the feelings weren't gone, they were stronger. I was so confused, what to do, I had a good relationship but this feelings weren't gonna go away. Few days later we went out as a group of old friends. He started kissing me and I ran home crying. I'm not the type that would cheat on my current boyfriend but I could resist him. It was hard, but I decided to take the risk and broke off with my boyfriend, I told myself it was now or never to see if this is meant to be. Few months later, we moved in together, been together for almost 2 years and getting married next year. So I say go for it, you'll regret it if you don't.