Put the Betterman (N.U.T.S.) techniques into practice again.
Again?!
Are you under the impression that you just act like a man only when necessary and then insecure the rest of the time?
Becoming a "better man" means just that, becoming a better man, letting go of your insecurities, accepting reality for what it is, being honest with yourself before you attempt to be honest with anyone else.
Let's start with number 1... You are insecure about your wife leaving you, having sex and affairs with other men (including a cousin).
It's a big one, definitely a doozie.
Analyze this feeling, this idea, this ugly truth that you seem to cling to so tightly.
Is this the woman she is?
Do you believe deep down that you're just counting the tick tocks on the clock till she cheats on you with another man?
I haven't read your entire situation but if she has cheated on you again, and you are the one trying to prove yourself to her and want to hold on to her and want her to stop cheating on you, you need to look at this very closely. If you really believe that your wife is going to cheat on you because of what she may have done in the past, then you have a trust issue. Is this something you can get over? Is she working to regain your trust, to build back the trust? If not, is she treating the relationship like it's a joke, or something not important to her? If so, that is your reality, a woman who you call your wife, who is not attracted to you, someone who is going through the motions of a marriage with you, someone who will cheat on you again, not if she will cheat, but WHEN she will cheat.
Is that a great relationship for you to be in? Always wondering? Always thinking about her doing this to you? Do you like this feeling of perpetual helplessness? Doesn't sound very healthy to me.
That's not how I would live.
If she is this kind of woman, someone who is going to hook up with another guy while being married to you and you're pretty sure about it, then let her go and find someone better for you.