I just wanted to say that my exAbf would do this frequently. He would stop drinking for a week, then brag to me that he could stop for a week, so that means he's not addicted. So he would drink again for a month. I would complain and then he would stop for 2 weeks. Then he would brag that if he could stop for 2 weeks, then he can stop whenever he wants. You see where this is going? Eventually it got to the point where he would say that he would only have 2 beers a night. No more, no less. He thought he could control it this way. WRONG! by the 5th night, it was 3 beers. By the 6th night it was a whole six pack. I didn't give him a chance to make it any worse after that. I just left.
I believe that some people can stop all on their own, without a program. However, his behavior sounds to me like he's just trying to prove to you that he can stop, then tell you that since he can stop, he's not addicted. It will just start all over agian.
I'm not trying to be harsh here, but there is a difference between being dry and being sober. My ex would also be very moody and cranky when I would make him stop. He became bitter and resentful that I was "controlling" his life. You don't have to be dependent on alcohol for it to be a problem. You may not have the classic signs of withdrawl, but eventually it could come to that if they don't get a grip on it right now.
Either way, if it's effecting you, then you need to get out. I have learned that being an alcoholic is only defined by weather they hold it above all other things in their lives. It consumes them so much that nothing else seems to matter. Regaurdless of how often they drink or how long they stop.
I hope the best for you.
Sarah