[OMFG!You'reActuallySmart!]

Given the strong feelings people have against your boyfriend, there's nothing you can do. If you go with him, people will question why and say whatever comments but if you begin defending him, people may question whether you are who you truly act like. In other words, are you really preppy or are you actually a goth, have you become a goth, etc...? Some questions may also be why you are with him, in that is there something you're trying to get from him because he's allegedly dumb and you're allegedly brilliant? I suppose you could tell others how he really is like but you would also have to show them. Chances are though, the labels aren't going to change much at all and since it's two weeks, just weather the storm.

Unlike the others who responded, DO NOT ignore the comments. Instead, allow the comments to come and know that the fact you continue to remain with him after each comment that may weaken the relationship, the overall relationship becomes stronger. It's like battle-testing the relationship, be aware the shots are coming at you and instead of skirting around them, go straight and let them hit head-on. You should first have him aware of your strategy.

As for your mother, you can tell her you'll break up but will remain as very good friends. In reality, you can keep dating but disguise it as though you're great friends who want to chat with each other as well as see each other in-person.