You shouldn't be embarrassed. If he didn't make a big deal about it then you shouldn't make a big deal about it. Believe it or not, there are some people out there that don't freakout over seeing someone in the buff. Personally I think way too much is made out of seeing someone nude in a non sexual setting. It just blows me away that people are such freaks about a naked human body. I think society would be so much better off if people could see a naked human body and just keep on going about their business like it's nothing. I don't want to turn this into a big rant so I'll just leave it at that.