I'm stuck :/

(BF:M, EX BF:K, GUY I LIKE:R) I have a boyfriend, but I like someone else. My ex boyfriend/ my best friends brother. now K knows I like his brother and my bf does too. I just started actualy talking to R tonight and my church. I really like R and there is a chance he may like me too. he doesn't know I like him but M and K both know. now the hard part is I also still have feelings for K but I like R so much more than both M and K! what should I do? should I tell R how I feel? should I dump M for R? should I just keep my mouth shut and stay with M? the problem is I can't get R off my mind. I talk about him all the time with my best friend Kaleah. but now that i'm talking to him my feelings are getting stronger! what should I do!? HELP