Is chunky monkey a joke?

My husband of 4 months grabbed my backside while laying down & said "hmmm, chunky monkey." When he realized - two minutes later, that I was completely silent & still, he tried to play it off like he'd just had an uncontrollable urge for ice cream. So now he thinks I'm "chunky" & apparently stupid, if he believes I'd fall for his lame attempt to cover it up. It really hurt. Not because I'm sensitive about my weight. I'm 5'8" & weigh 170. Not tiny, but by no means out of control either. I'm hurt because the one person in the world I trust never to be so insensitive & hurtful to me said something that is exactly that. It made me feel completely unattractive to him. When I've never felt that way before. Ever. I tried to talk to him about it, but he insisted it was a joke, not meant to be hurtful, I should be okay with it & not "make it a long drawn-out thing." Just to add to the insensitivity. My husband is also a kind, loving & funny man. How do I make him understand? Or am I wrong? Help.