I don't know what to do..

My boyfriend and I have been dating for 3 1/2 years and recently we've been not doing so hot, never seeing each other and arguing a lot. He also cheated on me twice with my ex best friend. I recently felt feelings for a friend of mine but never acted upon it seeing as I was dating my boyfriend. Well, recently I needed a break to deal with some personal issues and find myself again.. in the mean time my friend and I have been hanging out a lot and getting close.

I love my boyfriend/ex boyfriend, (whatever you want to call him since we're on a break) to pieces and i saw a future with him, but being with my friend makes me feel excited, refreshed, something new. But every time I see my boyfriend/ex I want to break down because I wanna be with him.

I'm so confused on what to do.....

My boyfriend/ex live together too and we're being mature and not kicking the other out seeing as we're both on the lease and I wouldn't have a place to live since my parents live in Pennsylvania...

Any help? :(