My heart goes out to you OP.
A close friend of mine is going through a very similar thing at the moment. Except she was also married, with kids. The affair prompted her to separate from her DH, she made arrangements to move out, then when the crunch came, her OM did not have the balls to do the same. Some of the things you have said are almost identical, word for word, with what my friend has been saying:
"if he had told me he didn't love me enough it would make it so much easier." Yep, she said the same thing.
I think what I'm struggling with is his relentless affection and telling me he wanted us to be together ... Amongst other grand statements he said that his feelings for his wife did not compare to how he felt about me and eventually won me over into thinking maybe we could make a go of things. I set my heart on it, then he decided to try again and cut me off overnight. - Again, exactly what happened to my friend.
Since he cut me off he sent me one message saying I am 'always there' and he thinks about me constantly. That is why I (idiotically) wanted to send one last email saying I think about him too and maybe if it's this bad for him then he's made the wrong choice. - Again, almost word for word identical to what my friend has said and done.
It's tragic, because the OM is clearly just being a spineless twat. He may actually believe all those things that he is saying, but at the end of the day, when push came to shove, he didn't love you enough to leave his wife for you.
I'm worried that my friend's OM will eventually be kicked out by his wife, and she will 'win' him by default. But what sort of a victory is that? You deserve a man who loves you so much he's prepared to do anything for you. A man who would turn his back on his comfortable life because being with YOU is more important than anything else.
Your OM is telling you that you're not that important. Listen to his actions, rather than his words, or his pathetic attention seeking messages. And I agree with the posters upthread who say that you need to focus on the negative stuff to get angry with him.
Heal yourself. Put yourself first. Because you can bet your arse your OM isn't putting your wellbeing anywhere near the top of his priorities right now.
(Sorry if I'm projecting a lot here. The similarities to my friend's situation are uncanny, and she will not listen to sense. I feel like I'm talking to her by writing it here but I hope it helps OP too)