hi, strong, welcome.
sorry you are hurting.maybe its time for you to do what you whatever you can to not allow yourself to think about her for awhile. i do understand how you must be feeling, my ah and i separated after 21yrs leaving me with so many questions about him, about me, and about us. it was so painful and the more i thought about him, the more confused and hurt i became. by the time if found this place, i was literally losing my sanity.
have you talked to a therapist, gone to alanon or naranon meetings? keep posting and reading.
i think because you could not except her behavior she may have gone to someone who will. its common for an addict to move from one enabler to the next. its not a personal thing, its just what addicts do. most addicts will do whatever it takes to be able to use their drugs without any resistance from others. i think one day you may realize she had done you a favor by leaving. it does get better but it will be a choice you have to make to get better. i'll keep you in my prayers