hi, welcome
the addict in my life is my husband of 23yrs. our relationship started out like yours and it took me 21yrs to figure out that nothing i did or didn't do would make him stop using, relapse or treat me any different. my decision to stay in a relationship with him was one of the worse decisions i've ever make. his addiction slowly began driving me insane so i had to separate myself after 21yrs of the back and forth.
sorry but in my opinion, the 'drawing in and pushing away" is typical addict behavior and trust me, unless he continues to be committed to his plan of recovery, his addiction will progressively get so much worse and so will you, if you decide to stay in this relationship.
what we suggest here is alanon or naranon, f2f meetings for family and friends, maybe you can search your area and began attending, my suggestion to you would be to focus more on you. maybe you could ask yourself if his behavior something you can live with for the long haul. keep reading, posting and learning all you can. there is a lot of helpful info in the stickies at top of the forum page.
it would be really good if he could go to rehab or detox but still, thats not a cure all. its only the beginning of his journey. recovery is hard work and it takes commitment. wishing you and him the best.