Boyfriend trouble help what should i do ?

okay well i have been with my boyfriend for the past 4 months and everything been going good but after a few weeks of our anni i found out he cheated on me . i asked him if it was true and he swore to everything he loved and especially me that he didnt. but after that he tells his friends to lie to me that it wasnt true but at the same time its true cause they tell me everything he does behinde my back. ive broken up with him but i got back to him cause ilove him so much and i cnt let go of him his like my life . what should i do ?