I gave my best friends ex a bj when we were drunk, do I tell her?

A bit of context first: My best friend and this guy were never actually official they would just sleep together when drunk and text quite a lot, they did this for about 3-4 months. He told her he didn’t want to be with her cause he wanted to be single, she still slept with him a couple times after it and it was clear she had strong feelings for him. They stopped sleeping together and then a few weeks later she found out she was pregnant but always knew she was going to abort it, she didn’t want to keep it for many reasons and one being that they weren’t together or ever going to be (she’s 20). However a few days after finding out she misscarried it and she coped with it well but you can tell it still affects her. They haven’t slept together or texted for about a month or so now.

So basically what happened was last night I was out with two of my friends and he was out too and we started speaking but just casually, he said he thought I hated him because of what he done to her and I said I did but not anymore as he was nice to her overall. I was very drunk that the night is a blur and there are many parts I can’t remember. My boyfriend of 4 months recently broke up with me and I’ve been feeling horrendous ever since. Anyways we ended up kissing outside and I ended up at his house. I gave him a blowjob but I couldn’t go through with having sex with him. I very nearly did but I stopped myself and then left his straight after.

I felt so terrible like I’ve never felt before in my life. She’s my best friend and she confided in me about him all the time. It was a stupid drunken mistake that I now feel has ruined my life. The week before this happened she sent him a text to ask him to meet with her to talk about the miscarriage situation as she feels he could help her feel closure on it. They’re meeting up this week and even though they’re not meeting up to talk about their relationship, she still clearly has unfinished business with him and I can’t believe I’ve done this to her.

He said he would never tell anyone, I messaged him after and begged him not to and he said that I don’t need to worry as he never would.

Do I tell my best friend about this (I’m scared because I can’t lose her as a friend because she’s means so much to me and I made the stupidest mistake of my life) or do you think I should not tell her as I feel it would only hurt her more and really affect herself right now as well as our friendship which I know she holds very close to her heart. What she doesn’t know can’t hurt her but I don’t know if this makes me a horrible human being for not telling her. Me and him will never speak again or do that again and I didn’t sleep with him but I did give him a blowjob which is why I feel horrific. I feel by not telling her will be protecting her as what happened with us was a drunken mistake and would never happen again. Am I a bad person if I don’t tell her? I just want her to be happy, get closure and finally move on to better things which she is starting to do now and I don’t want to ruin that all.

You're not required to tell your friend the details of your sex life. However, there's a chance that he could go back on his word and tell her - and it'll look so much worse if she hears it from him instead of you. It'd be better if she were to find out that it come directly from you.

Whether you tell her or don't tell her there's no way that guarantees that your friendship will last unfortunately.

yh but she is most likely to cut her off is she finds out she gave him bj weather she was honest or not so at least the friendship will last some time. whats the chances of him going back on his words

you just behsve stupidly when you are drunk- just like most people.