How to tell your family that you're seeing someone...?

Who by conventional social standards, can be seen as unattractive?

Hell, I never care for such trifling matters about the other opinion of attractiveness. Which was why I'm seeing this guy for a year (unbeknownst to the family) and actually do find him more than just physically attractive when we first met. Unfortunately, my parents expect better.

While my mom never liked me to even openly glance at another guy in front of her (she also despises the fact that my social circles lead me to be more closer to LARPers, geeks, and "those people who wear black"). But she expects that I 'naturally' should go for super model types. The chiseled cheekbones and pouting lips, etc. Didn't help that she's a size two in jeans before she had kids at 26 (I'm 21 and am size 14 for english jeans). My dad apparently complemented her as a couple before he let himself go at 21, AND he was used to being surrounded by attractive people. So while I helped my BF to get into a local hotel while he was job hunting in the country, I introduced him to my parents as a friend. My dad wouldn't mind at all, only that he'd be shocked if he realised I was hiding from him. It didn't help matters that after my significant other left, he snickered and sighed over my choices of friends often being 'overweight dweebs'. My mother, of course, would not let go the shock that his teeth weren't pure white (he just gave up smoking, so his teeth were a little stained), or that he is an endomorph in body type. Although she liked him well enough, she would've collapsed on a couch in shock and yell at me for being a desperate idiot.

Unfortunately, she constantly ignores time and again that my standards of attraction are different than hers. The multiple times she'd drag me across the room, the train, or the bus, to shove in front of guy who looks like an Abercombie and Fitch type did only to make more awkward the situation and I constantly had to tell her that seeing a guy simply of that kind, only leaves me feeling dead below the waist. Even more so, she constantly ignores that while my dates are fewer and feature more normal people (not tourists in vacation resorts like she used to live and work in), at least I never was stuck in a abusive relationship, with a guy who's only abusive by simply fooling her around and stringing her along (Like in terms of cheating on her, or telling her that condoms hurt on guys and that it's just silly to even think about contraception). Yup, she fell for guys like that because apparently they were hot enough to forgive for anything. Really, it's a case of dealing with a parent (one who needs to look in the mirror), and another who wants to force her choices on my life since as long as she can remember).