I think my boyfriend is cheating on me my friends say he is he says he's not. Plz No Rude Comments:)?

ok my friends say that he is cheating on mi but then when i go ask hym he says hes not and he said that the reason they said he got another gf was becuz he said he did cuz one of hiz friends said that I have another bf but i dont and what that friend of hiz told hym that for i dont know why and my best friend is tellin me this stuff and i just dont know who to believe and its kinna hard cuz he only said wat he said bcuz of what he herd but mybe he said that not just bcuz i said that mybe he said it bcuz its tru and it gets me soooo emotional and ive only asked him once if he was and he said no but i thought bout it somemore and i realli thnk he is i mean EVERYBODY is tllln me this sooo WAT DO I BELIEVE????WAT SHOULD I DO???