My opinion: this guy is full of it!!!
You have a son that needs you happy and well. I think that is your priority.
Not likely to have that sticking with a guy who was able to pull this on you. It has nothing to do with alcoholism or recovery, it is just about the kind of person he is and what is he capable of doing.
Remember he has been doing this to you it seems true your whole relationship, thus it has all been a lie, from the begining to the end. You don't know him at all, you only know what he wanted you to believe. He played you each step of the way, what is there to go back to?
Nothing but the idea of him, the person that doesn't really exist.
You met a man, fell in love with him, than you found out you were lied to from the very beggining, and that you don't know him at all.
You have a choice: either cut your loses, admit being played, betrayed, and the rest, learn from it, remove yourself, protect yourself and move on, hurt but wiser, or go back to him and expose yourself to finding more things he's capable of, whenever again he feels like self sabotaging.
If I were you I'd be grateful I found out now and not after moving in with him. You haven't sold your house yet. Your son can easily go back (I hope) to his old school, so in that aspect of it no unreapairable damage done.
You said you don't know what made you look at his cell. I wouldn't let that one slide easily. Maybe you were sensing something was wrong or maybe it is just your HP taking care of you. Either way, that is another thing to be grateful for.
And the way he is acting now, it speaks of everything but a grown up, responsible man. What is he, in high school, not taking no for an answer and getting his buddy (sponsor) to speak to you?
It is your decision, but I just have to say, if I were you, I'd plug off my phone, and go NO CONTACT for good, and run away from him as fast as I could.
I understand your pain, take your time to grieve something that never was what you thought, but protect your self and your child.
take care