I've been in this situation before and yes, I did break up with him. The relationship had lasted a year and we had been close friends previously. My parents never liked his 'arty' and 'laid back' personality. The situation came to a head when he defended me to my parents and they believed he had stepped out of line. They gave me the ultimatum of stay with him and the entire family will disown you. So I made my choice...
Until I am married and settled I will always take my mothers opinions of my partners into consideration. I know she will only have my best interests in mind and has a fresh outside perspective.
Actually it just sounds like your mother is a controlling whore who probably used similar ultimatums on her husband to keep him dusting the curtains. Tell her to stop bitchin' and get back in the kitchen. What, did she think you'd actually do something with your life rather than just sit there and be fat all day? 1 year relationship gone because of her "disowning" you.
In all seriousness though... If she was ACTUALLY going to disown you over him defending you... She doesn't have your best interests at heart as disowning you would emotionally fuck you for some time and she should want her daughter to be happy.
Also, she clearly wants you with a pussy who wouldn't stand up to the "oh so scary" parents... Let alone to anyone else... So honestly girl not only did you probably lose a prize of a man and thus are a silly whore but your mother is an idiot and you are for listening to her. It's your life after-all. I guess he deserves better than someone who will dump them after they were trying to defend them though...
Before you ask, yes I've been in that situation and yes my parents are strict as well. They threatened to disown me and did they? No. If they really do disown you they do NOT have your interests at heart. Hell, even if you were some fat junkie slut. Rehab. Not disowning. Lol.