Am I wrong? (Quarrel with SO)

Do you ladies ever feel like you nag your boyfriends/husbands too much? I do, but it isn't because I WANT to which is what he seems to think. You know... do the dishes, pick your shoes up, stuff like that. Well I have a new one for you that I'm pretty sure other girls aren't nagging their husbands about! Since our relationship has started (5 years ago), I've noticed my fiance forgets to brush his teeth. Gross right? He brushes them before work, but on the weekends he won't brush them. Not even if we are going out with friends. It's gross! I've asked him about it in the past and he just says he forgets. He's had many cavities when he was younger. I don't know if his parents just didn't teach him to brush his teeth or what, but it's weird to me. So we just had an argument because he hasn't brushed his teeth at all this entire weekend... so I asked him about it. I told him he's a grown man and should be taking care of his hygiene which includes brushing his teeth! He got very offended and acted like I was the meanest person in the world. I told him I was sorry for hurting his feelings but I'm not sorry for calling him out because obviously no one ever has! It's gross, a turn off, and I'm trying to help him. Personally I could never leave the house to go hang out with friends or anywhere in public without brushing mine.

Am I in the wrong for calling him out? Should I have just minded my own business and let him continue to disregard his teeth?