You've twisted yourself in circles trying to make your behaviour fit your "not cheating" morals.
I don't think I had even an emotional affair with him, I wasn't assuring him I'd leave my DH, or sleep with him, or even kiss him - it was all from his side. Yes I enjoyed the friendly flirting but I wasn't intending to take it any further.
It's the flirting that makes this wrong. It's the connection that you formed with him, that you should have had with just your husband.
Assuring him that you'd leave your husband isn't essential for an emotional affair. Many EAs have no such declarations - they are purely on the side.
If you'd kissed him, or slept with him, it would have been a full-blown affair, rather than an emotional one.
You formed a flirty bond with him. You started, and by your own admission enjoyed, forming a close, intimate and flirty connection. It's an affair in every sense other than that you came to your senses before you kissed. It was close, though, so that's not really a moral victory either.
You have to be honest about what this was, and why you're upset, so you're marriage is doomed. You're just going to sleepwalk into this situation again and again, and every time tell yourself that it was okay, it wasn't that bad, it was just some flirting...