blueraider...

You have been honest with her... that is important.. You need to speak with a counselor who practices within marriage therapy... it may be too late to salvage the marriage... but hopefully it isn't too late to salvage a respectful relationship that can help BOTH of you move on seperately while being a joint team in raising the children... outside of marriage... allowing both of you to explore new relationships and possible marriages to others.

It seems to me that the romantic love that you felt for her has changed into a sibling/friendship level.... it is very sad.. but I don't believe it is rare for that to occur.