What do I do ?

I have been in a relationship for almost 2 years now and I love my boyfriend very much. We have always talked about our future together and what not. But lately I have been kind of crushing on this other guy. I'm not really sure what to do about it. This new guy was my friends ex boyfriend and I know that's not okay but me and her are not on good terms. I'm just really unsure about everything and I need help on what to do