I won't name names, but I have been (and partly am) in the same situation. I know that they moved on with their lives, and I am genuinely happy for them. It would be so good to spend some time with them again though. I know. I know.
The way to handle this is to ponder: would you drop everything you have built in your life, divorce your wife, leave town and ask her to marry you? If the answer is no, you have the solution to your problem right there.

I thought at first reading the title that she died or something...  

 
If you can't accept the fact that you won't be able to see a hooker, you are not cut out for mongering.. She's a hooker man.. Not a  soulmate.. Not your friend.. Not your family..  

 
My loss story is the time I lost reading this drivel and answering it, for which I "apologize".

I've been seeing my gorgeous, UTR regular for four years now, once every two or three weeks.  She informed me two weeks ago that she had suddenly gotten engaged and had retired immediately.  We had really gotten to know each other over the years and had developed an amazing chemistry together.  While I feel a profound sense of loss, I also recognize that it's best for her to get married and move on with her life.  Loss, I've learned, is the essence of life.  Everything is temporary, so our ability to cope with loss will largely determine our ability to cope with life.