Why do some people come into your life when there can be no future to the relationship?

I have been dating this guy for almost four years now. And currently we are in a long distance relationship. Probably its the lack of constant communication due to which I started talking to one of his relatives without his knowledge and felt some connection. Both of us felt something but decided to cut off as this would be wrong to my boyfriend and would anyway have no future since we are different in many ways. It has been hard cutting off but I did it because I really love my boyfriend. I have decided never to tell my boyfriend about the whole thing. I just don't understand my feelings. I love my boyfriend and we are pretty serious about our future together but I really seem to like this other guy too.