You had a busy day at work but you tell your girl(23 year old) you are still down to hang out as long as you're in bed by 11. You give her ample time to make a decision. It's currently 4:30. She says she might stop by and that she might be going out for drinks with her work friends later. You tell her it's cool and expect to hear back from her.

At 7 pm, she texts and says "sorry, I don't think i'll be able to make it. I have to go buy work shoes N some other stuff. N then I'm going for a drink at 9." (It bugs you that she abbreviates the word "and" to "N")

Clearly, it's important for her to be on time to the bar to meet her work friends, who she sees frequently enough. You also know these "work friends" aren't her best friends, which makes it more worrisome. She doesn't really talk about them. Other than how she wishes she could hang with Emily more.

You know in the past she has had sexual relations with some of her co-workers, girls and guys. Two of which she claims have moved. This other guy still works there, you're pretty sure. Before you dated her, you knew about this guy. Enough to know she was cheating on her bf at the time with him. After she broke up with her bf she told this co-worker that they need to keep it professional and not see one another. Then you started dating her. You have been friends for 6 years.

You have no idea if this co-worker is at the bar with them/her tonight. But you have a feeling he hasn't been banned from their group hang outs. He is still friends with them. You don't consider yourself a jealous guy. You're human, sure. You feel the emotions, yes. But you have trained yourself to not be that guy. Whatever happens, just DON'T BE THAT GUY!! However, you have proof of nothing. It's your stupid subconscious taking control again.

So what do you do? You're not the kind of guy to go out and party to get out of this funk. You aren't going to cheat. Even though, you've had a history of cheating in the past. You're serious about your career and owning property and travelling. You enjoy playing guitar but you don't have the nerve to play for her. You realize this is probably a little possessive but you want her to chase you. You are a busy and interesting enough guy to not even need a girlfriend.
If she isn't cheating, that's great!
If she is, you'll never know. But you're not going to starting accusing her, or checking her phone or checking to see if she's at home in the evening. That's crazy. But you hate the idea of being duped for the next 1, 2 5 years...whatever.
You just want her desire you...a lot.