I am very aware that she's having a relationship with somebody else. My focus is not that somebody else my focus is her. I've gradually come to realize that I have no control over her and I can only control myself. So it seems the general theme of all this is to try and detach from your wife, get your own personal life in order to solve your problems, and show her what kind of person you are.
That is correct. But your focus must be on yourself not on her. What you must also accept is that she may never come back. When and if her current relationship doesn't work out she may just go on to the next guy, and the next guy after that who she is physically attracted to. In which case if you have worked on yourself maybe you will find someone who is truly worthy of your love and would never think to betray you.