The issue here is, G, you think it's pointless to make these changes because your wife wants out. You think that because she is already gone, why make these changes?
Don't mean to be harsh, but do YOU want to be the man-child you describe your self as? Do you want to be a doormat, someone who is disrespected by his own children?
These changes have nothing at all to do with your wife. If you want to only become a man who is respected and in charge of his own wife to get his wife back, well, then don't bother, because those changes won't be real. If you want to become that man for yourself, then then make those changes. They will be real if you do it for yourself.
Self-improvement should be for yourself, not to get your wife back.
