Wow, really tough one there Kieran, given her screen name is "yellowjasmin" and all...of course she's Asian.
So you've been dating 2 yrs. and this is the first time he's blown up at your dad? I don't buy it, but if so, you should ditch him.
I don't care if he's 19, 27 or 47, he should be respectful toward your dad. Period. You still care for you dad, and have a relationship with him, so he should understand that. He should ask his permission to marry you, should it come to that. If I were your father, I would've either b*tch slapped him silly, or had you two end your relationship.
I'm not even getting into how he treats his own family. I think you know deep down you should leave him, I'm just not sure why you haven't.