Seperated

[Dom R]

It is also hard to understand how someone who has loved for so long, would have done anything for me, cried at our wedding...now has no feelings or concern for me at all.

Most people who have affairs, end up in that way. Or the always popular, "i love you but i'm not 'in love' with you".

It's how he feels now. it doesnt have to be how he feels for the rest of his life.

Earlier I said biggest fear was infidelity...equal to that is divorce. What do I do if he says he wants a D ?

Say that you dont, if you dont want one.
Simple as that. Common wisdom is to not try to "argue him out of it", if he is clearly still involved with this other woman. If his mind is made up to go be with this other woman, than nothing you say is going to have any effect other than to frustrate him and make him feel like you are "the enemy", and "trying to stop him be happy".

Without trying to put specific words in your mouth.. generally, the idea is to let him takes the steps to pursue a divorce, if thats what he really wants.

Not help him. Just recognize that if he wants a divorce, then (with the exception of some states), he can file a divorce, and there's nothing you can do to "stop" him.

It's a tough realization to make. But, it's an important one. It helps deal with things down the road, to accept that you dont control him, and that right now, he's making choices that are very hurtful to you, and there's nothing you can do about it.

You can only endure, and try not to take them too personally.
(that's called "detaching". which is not the same as "giving up")