I've taken Ambien only once or twice with no side effects. My boy...

I've taken Ambien only once or twice with no side effects. My boyfriend however, takes it every night. He goes on ALL night eating binges, consuming almost everything in the kitchen. In the morning, the kitchen is littered with empty peanut butter jars, cracker boxes, cold cut wrappers, ice cream containers, jelly jars, left over take out boxes, etc. etc. This is what he consumers in just one night. This also happens night after night. I've asked him about it, and have had conversations with him while this is all going on. He seems lucid, but has absolutely no memory of his eating in the morning..But this new problem happened just the other night. We had what I thought was really terrific sex..You could have knocked me over when he said he did not have any memory of it what so ever This really scared me, and really got me thinking. He seems very sluggish during the day, without much energy. He has basically stopped going to the gym every morning, and I can see that he's putting much less effort into his very lucrative business. I've mentioned Ambien as a possible cause of these behaviors, but he doesn't seem totally convinced...What else could it be?