<human>: Summarize the given text in a few sentences.

M23, F22, 2 years

So, I dated this girl for 2 years, and we broke up a couple months ago for a variety of reasons. After having a couple talks recently, we have hashed out a large myriad of problems, and it is evident she would like to give things another shot. I will be seeing her soon (we live far apart), and have decided to tell her I would like to as well.

This being said, I made a mistake a few weeks ago. I have recently started graduate school, and after a night of carousing, and partially due to trying to figure out what I want as a single person, I hooked up with a girl. Normally I wouldn't think this was a big deal; I was single, and I wanted to have some fun. 

However, this girl is in my graduate school program, and she is probably going to be close to me not only personally, but professionally working on projects, for the next 5 years or so. I regret doing it, and we haven't even brought it up in any way since. There is no romantic interest, we were both very drunk, and she is pursuing another guy. None of our mutual friends seem to have noticed anything weird between us either.

So the problem: when I talk to my "ex" about getting back together, do I bring this info up voluntarily? I'll of course be honest if she asks, but I just don't know if it's something I should lay on the table. My two main concerns are as follows:

* I would like her to find out after visiting and meeting my friend at least once, so she isn't as likely to hate my friend from the get go

* She may not want to know about hookups at all... I'm not sure I even want to know what she's done since we've been apart

However, I can't help but feel guilty if I don't offer up the info right away, like I'd be hiding something from her. I also kind of want to know if this is going to be a future problem before officially getting back together. If it's a dealbreaker, I'd rather know now. 

What do you guys think?
<bot>: Getting back with ex, hooked up with close friend while single, and debating if I should tell her about this without being asked.