Is it normal that i want revenge this much?

Hello. All of my life I have been taunted by my older cousin. Since my family is Vietnamese, we are always together. When I was younger, he was always a dick to me, physically and verbally. It would get to the point where it was unbearable and we would constantly get into violent fights. Finally, my mother moved away for financial reasons so we only saw his family on major holidays.
Recently, my mother has moved back to the area. I'm 18 and in college and my cousin is 20. You'd think that with us being much older and mature that we'd both drop it. However, he is still such an ASS to me. He'll constantly make fun of my clothes and call me retarded in front of everyone. It's just so asinine.
During the last Thanksgiving that passed, I saw his girlfriend for the first time. I honestly dont think I have ever seen a woman in person be so sexy and beautiful. As soon as she walked in, I got a massive hard on. Shes got the nicest ass ever, big jugs, and curly, long hair. Not only is she aesthetically attractive, but shes smart as hell too! At the dinner table, my family was talking about her endeavours in college and she has a straight 4.0 and is aiming to become a pathologist. It's just so amazing.
I constantly wonder how my douchebag of a cousin landed with such a stunning woman. I will be honest; he does treat her well. They're always smiling and laughing and with all the times I have been over there, I have never seem them quarrel. However, he's only nice to her. He treats Everyone else like total shit. He purposely spilled food all over my little brother during Thanksgiving. I threatened him and now we're back on the bad side, so it got me thinking.
What if I stole his banging ass girlfriend?
Part of me wants to just bang her brains out, but the other part actually wants to get to know her and just take her as mine. It'd be so hilarious to see him get mad. I would FINALLY be the dick back to him for once, and it'd be great!
So, any tips? Nothing like, "just whip out your sausage". Lol. I wish it worked like that, but I dont think with this woman. Thanks guys