How would you feel?

I’ve been friends with this girl since high school. When we were in high school I had a bf and we broke up and then she started to talk to him but they never did anything. I didn’t care then. Then as we have become adults it’s like almost any guy that I genuinely liked and ended up not working out she ends up talking to them after me. Last night she told me this guy that I had REALLY REALLY liked hit her up on a dating app but she said she wasn’t gonna do anything. Then tells me today she gave him her number and they’ve been texting. Like she knew how I felt about this guy, like yeah we never ended up hooking up cause I’m not one to just sleep around, but she is which is fine that’s her body her choice. But WHY. Like the guy I’m currently seeing she doesn’t like because before we got into our relationship he hit her up on a dating app. But he NEVER knew she was my friend and we only were talking a few days at that point. Like it makes me feel some type of way. Like literally almost EVERY guy