At some point your wife was interested in you enough to marry you.
She probably has a higher than usual biologically based latent attraction to you as opposed to other men.
Also there are external things like a common home, children, finances, lifestyle, memories and history together that would actually cost her time and serious effort to pull apart. It is easier to stay together.
So assuming that the basic problem is “the blahs” and that you haven’t completely let your relationship flounder and run her interest in you down to absolute zero, or physically beat her, or cheated on her…
… she very likely remains highly predisposed to responding positively to you turning on the Alpha / Beta / Physical Fitness stuff.
Your wife is the easiest person to Game that you know.
You can do this.