<human>: Me and my girlfriend of around 2 years broke up around 6 months ago.  I loved her (and still do love her), but there were a few issues that led to us breaking up, particularly that we'd hardly had sex in over a year.

I decided I was going to break up with her but left it around a month before doing so, because when I decided to do it really wasn't a good time, for various reasons.  Around this time another girl started flirting with me, I flirted back, and on a night out we nearly kissed.  We stopped when she said that we shouldn't do anything because I was in a relationship, and I agreed, although to be perfectly honest I don't know what I would've done if she hadn't stopped it.

In the days after I was in a bit of a wreck, not knowing what to do or how to feel.  I knew I shouldn't have done it, but I wanted to be out of my relationship, and I was a mess.  On another night out a few days later, I did kiss someone else, although I believe she initiated it and I pulled away after a couple of seconds.  I was very drunk this time, and I'd find it much easier to forgive myself if I hadn't carried on talking to her afterwards.

So here's the thing.  Me and my ex still talk all the time, we're such good friends, and I feel incredibly guilty for what happened.  Part of me feels like I should tell her, both because there's something in me that feels she has the right to know, and because I feel like I deserve punishment.  At the same time, another part of me feels she'd be very upset if I told her, and although it was wrong, there wouldn't be any way to tell her without making it sound worse than it is.  I feel like a terrible person, it's dragging me down and I need to decide what to do.  Any advice would be much appreciated.

Can you succinctly summarize the text in 1-3 sentences?
<bot>: did something I shouldn't have done when I was with my ex, need to decide whether to tell her or not.