Longterm affair with married guy?

I’m 20. I’ve been having an affair with a married friend/co-worker (who is 30) for almost a year now. In the beginning it was just flirting but as the months progressed we did have a physical encounter. He was upset after because this was the first time he has cheated on his wife since he married her two years ago (he has a history of cheating and did cheat on her while they were dating which she knows about but she does not know about us). We didn’t do anything and hardly even flirted for a couple months after that. Then I found out I was going to be moving out of state in a couple of months. The day before I left, we had another physical moment.

I have been gone for almost five months now but will be coming back in a couple of weeks. The entire time I have been gone we have flirted and had “dirty” conversations over text. Like, not just sometimes, but almost on a daily basis.

The thing is: he is one of my closest friends. And aside from all the things we “do”, we are very close friends. I can tell him anything. We used to hang out all the time, going on hikes and watching movies and stuff. His wife was usually unaware that we were hanging out. I am very emotionally attached to him.

I have never met his wife. I have almost had to meet her on a couple of occasions, but didn’t. I feel so awkward. One day after work

I have gone back and forth between feeling guilty and feeling like it’s not my fault what HE chooses to do. I would hate to be her because I know that its awful. But at the same time I know that if he isn’t doing things with me, he would be doing them with someone else.

Part of me has wanted to stop it for awhile, but I can’t help it. And I do like the attention. I feel like other people think that I’m this horrible person (there are only a few that know) but they wouldn’t say that to my face. I have put myself in her (the wifes) shoes and I know I would feel absolutely AWFUL if it were me, but I continue anyway.

Some of the time I really don’t feel guilty at all. I am not the one making the bad choice: he is. I shouldn’t have to feel bad because he is choosing to do this, right? I should just enjoy myself. I’m young.

Right?