20 years, and now I'm lost...

We were married for 20yrs and have three beautiful children. It’s almost 2 years since we’ve separated. She was all I’ve ever wanted. When I met her till the day we split I was never thought I deserved such a beautiful woman. She was (and still is) highly desired by men, but she was so down to earth and didn’t ever use that to threaten me. She was high school homecoming queen, and believe me every guy desired her, but when we married (she was 22) she was a virgin. I know all her friends and guys she dated and they all confirmed. So I have no reason to doubt. She was a very good faithful wife, and excellent mother. I made a very good living, and our family was comfortable. I shopped and cooked dinner often while she shuttled the children. I would make special dinner, and bring flowers home spontaneously. I planned trips, and get always.
When we began having problems around year 13, I agreed to go to individual counseling because she thought I had low self esteem (I did/do). I read mountains of books. I wanted to be what she wanted/needed. After a few years we started couples counseling. We tried several different, but the underlying theme was that I was the problem. Funny thing is that I ( and still do) believe it. To be fair, I did have my issues. I would shutdown because I would feel so inadequate, and then she would misinterpret. Even though I told her it had nothing to do with her. I would get short with her at times too. She claimed emotional abuse before we split. I was devastated. I would NEVER abuse her. She was my everything, but obviously I did not communicate that well enough, although she said when we split that she knew I loved her deeply.
During the 07 economic turn down, we were building our dream house, things came tumbling down and I pretty much lost everything. I tried to insulate her and the family and didn’t tell her the stupid things (gambles) I was taking. That was the end basically.
For a year I went through the most pain I’ve ever experienced. The loss of my dream girl, and the guilt of what I did financially. I wrote so many emails pouring my heart and feelings to her, but she never responded. That hurt. So, sadly I’ve taken all that hurt and turned it to anger. I’ve been so mean and hurtful to her. I wanted her to hurt as much as I she made me hurt. I still can’t stand to see her or speak to her because it hurts so much. Not because I dislike her, but because I am still so attracted, and jealous of her...It hurts that she had never once wanted to talk to me about us after we split. 20 years!
Now after 2 years I find out that she is away with a boyfriend for the weekend. It kills me. I’m devastated. I knew she would have no problem moving on, with her drop dead good looks, and sparkling personality. It just magnifies my shortcomings. I know for a fact I’ll never find another to replace her. I’m feeling so lonely and unattractive. I can’t get out of my mind the picture of her and another man enjoying the weekend, sleeping together, etc. It’s unbearable.