Dont Judge.. Help?

my boyfriend and i have been in a 6 months (tomorrow (: ) relationship buut, through these 6 months has been a series of arguments & lies & him drinking & cheating & ive FORGAVE , FORGAVE , FORGAVE .. bc i really loved him but after him lying and continung to lie to me i think i lost interest.. w/o realizing until his friend, came on to me over text.. we both know that we cannot even think about it but this guy confessed his lust i might say, he's definitely attracted but i cannot say love b/c its not that, & i dont want to lead this guy on, but not off either bc if my relationship continues to be toxic i wanna have the strength to want better for myself but how do you throw 6 months away.? i have hung out w this friend once & it was an automatic connect & i liked that.. we have a lot in common & he's someone that values my opinion as well as his ... my boyfriend is very self-conceited & ive tried to talk & be patient & wait for him to understand my point of view but it doesnt happen.. i dont know what to do, thoughts...?