Girl slept with someone right before exclusive

I’m a 22M. From the start I wanted something serious and exclusive, but she didn’t. We ended up in this non-casual “casual” friends-with-benefits situation that felt like a real relationship anyway. She wasn’t ready to commit even though I wanted it right away. I was okay keeping it casual for now since I was enjoying it and figured I’d let it run its course.

She had valid reasons I suppose, she wasn’t over her ex of over five years, wanted to enjoy being single, and I was supposed to restart my company in a new state in four to six months (she adamantly refused long distance). We saw each other six times a week for a couple weeks. After a week of seeing each other she re-iterated not being ready to be exclusive.

While I was out of town for work for a couple weeks, her and I were talking all day while I was gone which makes this sting more, she hooked up with another guy (casual FWB) she’d been seeing. After that she stopped seeing other people on her own.

After my work trip, I got a lot of work in state and decided to double down and stay, situations changed and I’m not moving anymore, she told

me after she learned I wasn’t moving anymore realize a relationship could happen. Now I feel weird moving forward with someone who didn’t want me seriously at first. I’m new to casual dating, usually if someone says no, I just walk away. It’s a pride thing.

This happened 2 months ago, I’ve slowly been processing my feelings and deciding if this a long term thing I want. She got over her ex in the same time also, and she keeps threatening to ask me out if I don’t do it soon.

We get along amazingly, I really like her (and she really likes me, I can tell), and this “casual” thing was better than any real relationship I’ve ever had. We’ve been great friends for a while too. Just deciding if I want to make it official/see it as a long term thing.