Tl;Dr ghosted after 3 good fucks. What happened?

I met her through tinder and we both started rock climbing together (she was going for <1 year, I've gone off and on my whole life, decided to join the gym though). I pushed to get a drink and chill afterwards so not just climbing partners. A few times she flaked on climbing but invited me over or came to mine and we fucked. I fucked her real good at least from a physical standpoint, I have sensitivity issues and she liked it fast and hard, so it was perfect for me. Even made her squirt the last time. She comments how tired she feels after sex and how it's supposed to be the opposite - good I think. We only had sex 3 times. I think twice we climbed and no sex, Friday night and I already had plans type of situation. So things are good and warming up from my perspective. I'm pretty uninvolved emotionally, just text for logistics and no chit chat texts from either of us.

The whole time she talks about this other guy she climbs with. I say I did something or wanted to do something, or even my pattern of speech she says how he did that and that we're similar and would get along. It wasn't just a single offhand comment. I just brushed it all off and ignored it. Course I suspect she might be fucking him too, but no big deal. And I actually think they were not fucking, but just a hunch. It's weird though like every time I hear about him, I even suspect maybe she wants to be double teamed so she's trying to warm me up to him.

Then one day she says he's making her go to a concert and she's going to take e for the first time (she's 23, he 26, me 27). I play it cool, say how I put all that behind me, she calls me old. We fuck then and then another night before the concert. And make plans to climb a few days later after the concert. That day comes, she can't hang after climbing Friday and we make plans Saturday night (after she climbs during the day with this other guy and her roommate). Saturday comes I hit her up she replies once and then ghosts I haven't heard from her since.

So my own reflection is this guy confessed his love or whatever on e and they formed some hella close attachment. I dodged a bullet because prior I saw mostly green flags, good family relationships, small hometown, not degenerate partying, not a picky eater, liked seafood, etc. Part of me wonders if I could have done something to at least have kept fucking her and not be ghosted. Any ltr potential dissolved when she started talking about e. I'm not hung up on her, a little sad to see all that potential disappear, just surprised we hit the 3 fucks threshold to have her ghost me. I'll certainly run into her again at the gym too, so idk what her thought process is if she's just too scared to deal with me and her feelings.