I think your H is smack bang in the middle of a full blown mid-life crisis - and that makes your task that much more difficult.
I've stayed out late and I'm in no state to post sensibly tonight (one too many glasses of wine I'm afraid) - and I'll come back tomorrow first thing - but in the meantime go over to the MLC Forum and read some of the resources at the top of the forum. I think it will really ring true for you.
I actually wonder if you should move your thread over there, because there are quite a few woman in similar circumstances as you (very long marriages, children, husband gone mad ... that sort of thing!!).
He may have said that awful stuff about not cheating, but really he said it to defend himself. He was put on the spot so he lashed out and tried to represent himself in the best light he could. I suspect he doesn't really think that in his heart - but he had to say something. Even men in mid-life crisis don't like being called a cheater. Although if it walks like a duck and quacks like a duck .....
I'll be back first thing in the morning.
Hang in there Penny. You are doing well and you're going to be OK. I know it.
V
Never make someone a priority, who makes you an option.