How to end it forever or should i work it out?

Going on 3 yrs with the same guy that useto mean a lot to me and made me feel love dearly, now we have ran into some major problems. This neighborhood ghetto round the way broadcast how her and my boyfriend been fooling around but tells me that they just text no phone talk cause she has a boyfriend and that her and my boyfriend just have . I never ever caught him and have access to everything even though we don't live together I have a house key WHY WOULD HE CHEAT WHEN I HAVE A KEY AND KNOWN TO JUST POP UP ANYTIME??? anyways I call myself working it out with him but I'm going crazy one day I'm cool and the next I'm crying hating him. No I'm not in love anymore cause he want even confront this tramp and that makes me think she is telling the truth. Then it is so hard for him to treat me nicely for a long period of time before he's back to being mentally abusive to me. I dont believe anything he say to me and I feel like he is the enemy. More and more I feel like he don't love me. He make me feel so sad never happy. I wish he feel what I feel