Slept with my best friends boyfriend

Last night I was at my friend's house (different friend) and we were bored there was nothing to do and we wanted to smoke.. So she called her dude and he said he had some bud and a bottle he said he was with someone but we didn't ask who

They showed up and he was with my best friend's boyfriend (let's call him Jay)... We ended up going back to my friend's dude's house. We started drinkin and chilling and the whole night Jay kept looking and me. He is so hott I always thought he was cute, Puerto Rican, tatts, green eyes, sexy ass lips, and just the way he talks and idk he's just sexy. We kind of used to talk a few years ago but not for that long and never had sex before. he's a few years older (he's 23, I'm 18 ) But back then he said I was too young and we stopped talking. I was like 16.

After we were chilling we needed some more bud and we were gonna get some coke. And my friends dude told her to take a ride.. He told me to stay with jay... And at that point I already knew when they left something was gonna happen just the way he was staring at me from across the room the whole time we were there.. And biting his lips

As soon as they left he came and pulled me up off the couch and started kissing me and rubbing my 😺..I was already drunk and on coke and it felt so good at the time and they way he was kissing and biting my neck I knew I should have stopped him but I couldn't.

After they got back and we partied and did more coke and drank even more ..long story short we ended up having sex in his room at like 4am. The next night he brought me home. He said he is breaking up with her and wants to just lay low and just talk to me. and wants me to stay with him at his place. (Not that I want to, that's just what he told me today)

My best friends on vacation and comes back on Friday idk how to face her. Should I tell her? Or just keep it a secret and let it be?

Before everyone attacks me and calls me every type of slut, whore in the book just know that my BEST FRIEND is known for sleeping with guys who have girlfriends... She's no fuxking angel