boyfriend cheated

what do i do…

my boyfriend and i have been together over a year now, we were having trouble with our relationship and he spent a night with my best friend at the time. They didn’t have sex but they did touch intimately - he says he regretted it straight away, she says he was asking for more and making out as if he was begging her for sex.

While i would believe her, my boyfriend was inconsolable when he told me (after a few days of lying to me which is why i also don’t fully believe or trust him) and said that he had considered breaking up with me so he didn’t have to hurt me by telling me what he did. She is desperate for me and her to remain friends and her explanation is that she didn’t want it to happen and that he is a bad person - but then why was she there and why did she stay…

I don’t know who to believe who to trust - when she tells me things he’s “been saying” since on text it hurts but she refuses to send me proof of this which makes me believe that it isn’t true, the only proof she has on him is him begging her to not tell me because he wanted to.

What do i do!!!

I don’t want to lose my boyfriend i love him and the last week before all this came to light we were really rekindling our relationship and now this… I have told my friend i don’t want to be her friend anymore and that friendship is cut off, but what do i do about my boyfriend who do i believe??