<human>: On Monday, I found out that my now ex that I was with for 2 years had been cheating on me with a mutual friend who was also in a relationship at the time. I completely flew off the handle at him and said some pretty awful things that I now kind of regret, like "you are a waste of space, leave me alone", "I wish I had never met you", and some additional nasty insults/namecalling. To be fair, I was reacting to the fact that he initially said that his cheating was my fault because he knew that he wouldn't be able to handle an LDR once he transferred colleges but tried it anyway for me because I "wasn't getting it through my head that there was no hope for us". He was also being pretty nasty right back when I confronted him and he wouldn't even apologize initially. Later, he actually did sort of apologize and expressed regret for sleeping with the other girl, but still wouldn't really take responsibility for what he did, so I continued to be kind of mean in my responses. I don't know what to think or if I should even feel guilty, but I do. He's blocked on everything, but do I temporarily unblock him to apologize or do I just move on? I need help, Reddit, I'm normally a very calm and rational person and I don't like the way that I handled this.

Can you give me a shortened version of the text?
<bot>: I resorted to some nasty namecalling when I found out that my ex cheated on me and I'm feeling pretty guilty about it. Do I owe him an apology or not?