I think you should just ask him and don't let it rest until you get an explanation that you feel ok with. All of the suggestions above are possible. Do you feel any guilt for having the break? Maybe there's some counter-transference on his part and he's responding to your guilt on some level. Maybe there's some other reason why he feels the need to maintain such firm boundaries. Either way if it's a problem for you, you need to bring it up.

I stopped trying to be 'good' a while ago and found my therapist to be much more engaging. Now I try to annoy him occasionally, just for fun. Gently pushing boundaries can be frightening but fun too sometimes. He can also be rigid and unhelpful at times but is always willing to talk about it.