So, this actually happened a few years ago, but i still feel guilty about it. I dated this guy for 6 months. It was going really well, until depression kicked my butt hard. I decided to break up with him for both of our sakes. I couldn't handle a relationship at the time.

I had an ex who I'd been in a LDR with several months before this. We stayed friends, and even though we didn't really hang out, we texted almost daily. No cheating, no sketchy topics, just friend stuff. The aforementioned now-ex bf was always skeptical of our friendship, but didn't make a big deal of it.

So I broke up with this guy in the evening after we got back from dinner. I told my ex about it, who happened to be in town, and he came over to give me emotional support. So he comes over about an hour later, and... things escalate. I end up sleeping with him 2 hours after I broke up with the other guy. 

I know I didn't technically cheat, but I don't know if I technically did anything wrong. It's been weighing on me for quite a while.