What can I do about this situation?

It's about a guy. I really like him. My crush on him is quite intense. When I first saw him I liked him and flirted with him but I never felt he would go for me. So I started going out with someone else. Someone I have committed to. Unexpectedly the other guy approached me and asked to get to know me. He explained that he had been trying to get a chance to approach me to tell me how he felt but he couldn't get an opportunity. He said it was only when he realised time was going that he got more ascertive and came after me and even then I see that it was difficluut for him to get to me. Looking back I do realise that there were signs he liked me but I didn't make myself accessible. I'd rather be with him and if I had known sooner it would have been him. We share a great connection. Now I'm really sad cause I feel I have missed out but also I feel I disappointed him and I feel I may have led him on only to disappoint him. He was really brave to come to me when he did and in the way he did. I also feel that because I committed to my current bf I should stay and see what happens but I just feel that the whole situation is just so sad and I can't stop feeling sad. The other guy doesn't approach me anymore and I suspect he is trrying to stop liking me as he doesn't respond the same to me anymore. I almost don't want him to stop liking me and I also feel sad that he has. I actually looked to him the other day and he turned away and I was actually hurt by this. Help me gain perspective please.