I Slept With My Coach, Now What!? [18+]

I need some advice. First of, let me start off by saying everyone in this event including myself are 18 years old or older.So I play softball recreationally. A sport I picked up while living on my own in Northern California. Anyway, about a year ago, I decided to move back to LA to be with family.I decided to check out and join the gay softball league to make friends.Huge success!Anyway, I see this coach who Is a bit older than me (I'm in my early 30's, he's mid 40s). I thought he was very handsome hairy guy, but definitely intimidated me. I have a few run inns with him, where he waves or tries to say "Hi", but I'm usually oblivious, so he makes it more obvious. I start saying "hi". At this point, I don't know the guy, just know he's a coach from another team.We'll the season ends and my team breaks up. I'm a little sad, start trying out for new teams, and on my way out of one of the tryouts I look at one of my hook up apps And notice that the hot coach I had checked me out.He keeps doing it for about a week and one of those drunken bar nights I say "Hi". We talk online and after a couple of hours of messaging, he send me a pic of his manhood (it was impressive) and invites me over. I Ubered over there it was fun, but ended quicker than I would have liked.Anyway, that was that for me, or so I thought. We didn't really talk. Then a tournament was coming up And I wanted to play. So when I saw a post about a team needing players I volunteered. Didn't know what team until I showed up at the practice and it was the coaches team I hooked up with.We both pretended like nothing happened and just practiced. Really enjoyed the practice and became quick friends with a young, cute 22 year old. He's a really nice guy and we've become good friends. A few weeks later, I find out that him and the coach use to date when he was 18. The worst part is that this young guy is still in love with the coach and possessive of him.We went to the tournament, where I find the coach trying to convince me to play with him full time. He really needed someone like me who knows how to play the game and call the plays. Most of the people on this team are pretty green. And to be honest, I needed a team. So, I caved and joined the team full time.Now the young guy and I are good friends and I'm afraid that he'll find out that I hooked up with the coach. Should I tell him? Wouldn't it be worse if he find out later? Or should I just let it be?