Let her go. She deserves better than you. Be happy for her and give her the divorce she wants and the happines and respect that you are not giving her.
Normally I am pro saving a marriage but honestly, you appear to have issues. Work on those before you even consider your Wife or any other relationship for that matter.
Me:48 W:55 M:22 T:23 Bomb:19Nov09 S:15Jan10 D:11Feb10 EA:Confirmed on 20Apr10 Fast track to her divorcing me