Should I tell my bf what happened or keep it to myself?

So my friend had a little reunion/ get together with some close friends of ours that we haven’t seen in over a year because of Covid. So these friends I completely trust and I feel safe to drink with them and I feel like no one would take advantage or let me do anything dumb. So anyways I got pretty drunk and I had to use the restroom. And the only restroom in my friends apt was in her room. So I go and use the restroom and when I get out I lay on her bed. Shortly after my guy friend mike walks in and uses the restroom and when he gets out he also lays on the bed. I didn’t mind because like I said we are all close friends we see each other like family. He was on one side of the bed and I was on the other. We are just talking like normal and then he got closer to show me something on his phone. And then after he showed me what he had to show me he asks “do u want to cuddle?” And I say “umm nah I’m good” and I get up and go back out with my friends. I didn’t think much of it because mike is a very huggie and touchy person sober so when he’s drunk he’s even more of a hugger. And I also said no because I have a bf of 4 years and I just thought that would be disrespectful. So times goes by and I need to use the restroom again. When I walked into the room mike was in there talking on his phone with his roommate. I do my business and when I come out he’s off the phone but just scrolling thru IG. As I’m about to walk out he says “wait come here?” And I walk back and say “what?” And he says “no closer” and grabs my arm and pulls me closer. And when I’m right in front of him I see his hand about to reach my breasts. I slap his had away before he had the chance to touch me and I just walk straight out and back with my friends. Maybe like 30mins later I text my bf to pick me up and he comes shortly after and we go back to his place to spend the night. I didn’t tell my bf what happened last night because I didn’t want to worry him or make him feel insecure. He has complete trust in me and knows I wouldn’t cheat on him or let anything happen. The only reason why I didn’t tell him is because he is insecure of one of my other friend Josh. Before I got with my bf Josh had a thing for me and tried to pursue me but I wasn’t interested at the time. He is a good looking guy but I never saw him anything more than a friend. And when me and my bf were friends I told him about Josh and all the things he was doing to get me. I remember at the time my bf when we were friends would ask me if I was interested in Josh but I would say “he’s good looking and all and we have a great relationship but I just don’t see him in that way”. But now fast forward in time whenever he knows Josh is going to be at a gathering I can tell he feels off about it. We had a talk about it and he said “well I know nothing happened between u too but idk he’s a good looking dude and every time u run into him u seem happy to see him” and I said “well u have nothing to worry about. Yes whenever we run into him we hug and seem happy to see each but that’s because we had a good friendship so it just feels good to see an old friend.” I hardly ever see josh maybe like once a year I would see him at a gathering.

So anyways I don’t want my bf to feel insecure again with what happened.

Should I tell my bf or just keep it to myself.