No, I'm not promising that if you "change your life in just the right fine-tuned and perfect way it will turn her around." You CAN'T, after all, change her. What I've been trying to say is that if you should change your mindset, stop viewing yourself as a victim and want to begin living with integrity again--if you came to a place where you were ready to offer her the option of EITHER remaining stuck without you OR exploring a mutually satisfying M with you--if you were ready to grow as a sexual AND emotional being, only THEN would PM have something to offer you.
No, you wouldn't need PM merely to "find a new partner." It's more about, as Y at H points out, discovering new dimensions to sexuality (and the self).