Max...I know you are struggling...but for me, it would not be hard to imagine how the betrayal would feel.
In my marriage, I am the one who cheated...and it was a huge mistake.
However, in my current relationship, I would never cheat, mostly because I know better now...but also because I CHOOSE not to even entertain any thoughts of infidelity. I CHOOSE to be faithful, because I love and want only him.
So I think it is that choice you made to be unfaithful, regardless of your reasons, that your husband feels cheated about. He choose to be faithful, and you chose to be unfaithful. So he feels cheated out of a faithful marriage, something he held sacred to himself. Regardless of any other problems in your marriage, he always felt "well at least we have been faithful". Without that, he feels cheated now because the rules were different than he thought.
In my current relationship...I know that if he ever cheated on me, I wouldn't be able to be with him anymore. I could forgive him eventually and maybe even be his friend...but I could never kiss, hug, or have sex with him again...and I wouldn't want to even try. I would just let him go. So for some reason, I am able to imagine how I would feel if he cheated, and that is how I know the devastation to my ex-husband...in fact, I totally assumed my ex-husband would leave me when I confessed my affair to him - I didn't even think he would want to try. He did stay with me and we tried, but it was never fixed and we ultimately divorced over 10 years later...both of us unhappy that whole time.
I think you have the right to ask your H for forgivness and another chance...but you don't have the rigth to demand it from him. If he will not willingly come back and give it another try, then I don't really think you should chase after him.
I do wish somehow you could imagine yourself in his shoes so you would understand. For me it is easy to imagine how I would feel...