A girl I’m talking to slept with someone

So I’ve been talking to this girl for a little over a month. We aren’t officially dating. She is currently in the process of moving and she is currently in a different state. She just told me recently that she was “super effing horny” so she found a guy on tinder and had sex with him. The question here is am I justified for feeling angry or upset? Or should I just cut communication with her since we aren’t dating and this obviously means she most likely doesn’t have any interest in me?