Hope4us, You may not realize it, but you are at much better place than most of us. It is more promising when the OP leaves your spouse. Yes, they are still mourning for that "love", but they are not in direct "competition" with you.
Have you read ever read "How to Save Your Marriage Alone" by Dr. Ed Wheat? It is a very short and easy read and very inexpensive. You can find it on Amazon.com. I think that it would benefit you greatly.
Yoyo
Life's challenges are not supposed to paralyze you, they're supposed to help you discover who you are. -- Bernice Johnson Reagon