This is the point where you need to have some kind of internal conversation with yourself so you're not bowled over by his vacillating. In that, you convince yourself of the truth--that you are an amazing person and that you deserve someone that will love, cherish, and honor you; not sleep around and want you back just because you might not "be there".
If he wants to do the work to change, let him prove it by actually doing the work. Stop listening to any of his words, and ask for actions. Then, after significant actions take place, maybe you consider reconciling, but only at the point where you believe his changes are real and that they will stick. This could be years down the road, given the severity of his SA.
He might find someone else in a week, so that's why his words mean absolutely nothing to you. You are an incredible person that doesn't need him; he's realizing that he needs you. Or someone, at any rate, because he is so utterly empty inside. Let him learn to fill himself up or continue on his addiction--the ball is in his court.
You just worry about you, and making you happy. And yes, seeking out some expert help is a great idea.
(((HC)))
It is in the shelter of each other that people live.--Irish proverb
