<human>: I have fucked up big time.. I don't know what to do!

Thursday night I slept over at a mutual old-time friend's house, let's call him X. There was a bunch of friends and one of them is my boyfriend's best friend. There was a lot of alcohol and other drugs.

I slept in the same bed as X, we didn't kiss or fuck, he was feeling me up but I didn't let him touch my ass or breasts, I'm not sure how long this went on but I'd say about 10 minutes. I am an idiot.. I clearly was not thinking at all!!!!

I texted my boyfriend in the morning and told him that I cuddled with X, I wanted to tell him everything when I see him face to face next week, he lives abroad and speaking about it on the phone didn't seem like a good idea.

Today his best friend told him that he heard us breathing heavily and giggling, so now my boyfriend thinks we had sex and doesn't believe that I was going to tell him when I see him.

He is refusing to talk to me now, says he needs time which I understand, so I'm thinking about writing him an email to apologise and explain everything.

I don't think he wants to break up with me (hopefully), but our relationship will probably never be the same again.. we had so much trust in each other, I have been extremely honest and open with him from day 1 and now I have fucked it all up...

It's not even about sex, it's about the fact that he thinks I wasn't going to tell him.

I don't know what else to do.

Could you distill the essence of the text into 1-3 sentences?
<bot>: Fooled around in bed with a mutual friend (no sex), my boyfriend doesn't believe that I was going to tell him about it, thinks we had sex.