Did we handle this the right way? what is he thinking?

I think he was using 6 months generally. Not literally. Personally if my boyfriend would have asked me if he was husband material after 5 months of dating I probably would have ran in the other direction. Its too soon to be thinking of all that. Why not just enjoy what you have while you have it? Obviously your boyfriend wants to be with you, and I can't imagine that anyone would date someone for 5 months if they didn't care about them or couldn't see themselves together down the road. Take is slow, enjoy it before things get complicated. Maybe you should give it another 5 or 6 months before you ask him again. Or maybe wait until he brings it up?