How do stop thinking about this and letting it bother me?

I was talking to this girl that I recently met on an app, we had talked for a couple of days everything was going good. Then about three days ago we had gotten into an argument about something. and she stopped answering my phone calls and my messages. so I hadn’t really been speaking to her but then yesterday she tells me that she had invited another guy over to her house to spend the night and that they had sex. And to be honest it has really upset me because even though I wasn’t dating this girl I really did like her and I’d like to talk to her and you know I could’ve seen eventually getting into a relationship with her. And I don’t know why I feel feel this way but I just feel betrayed and really upset and pissed off about it even though technically we are not even dating but I didn’t think that she was that kind of person and you know I did like her. But obviously now after something like that obviously I know not to forgive her and to not give her another chance and there’s no chance of me getting into a relationship with her now because clearly can’t trust her and I don’t want her if she’s doing something like that so I’m not gonna give her another chance but how do I stop feeling so crap about it and just move on and forget about this and about her and just move on and not be upset anymore

Updates
10 mo
And just to add-on I was gonna let her live with me too. Because apparently she has a bad home life
How do stop thinking about this and letting it bother me?
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