You cannot turn your feelings on or off; they are not under your control. I would let the divorce happen, get into therapy for myself to learn who I am, and see if in six months or so your wife would date you, literally. Not though, if you are still grieving over someone else, that would still be trying to catch her on the rebound.

You cannot get back what use to be; that is gone, like trying to get back one's childhood; you only have "now". Get to know yourself and how to keep yourself out of temptation's way and how to communicate and correct relationship problems as they come up. There might be a spark of feeling still between the two of you but that feeling is not the same as the relationship itself. We all like and love multiple people at once but commitment is an exercise that takes hard work and practice and you don't have that kind of time now or the knowledge and experience to get it right yet.