Maybe he doesn't want to hang around with you because he knows you want his wife.

his wife wants me... lols
but like these guys said, she's probably checking out a lot of other US guys since she's been in the states. it's all new to her so she's absorbing the atmosphere and the people. the only thing that keeps her tied down is that she's married...
i'm sure he puts her on lock-down away from a lot of folks.
If you really respect your cousin then you willstay away, treat her as a sister and make sure she realizes that if it becomes unclear. It's not worth ruining your cousin's life and tarnishing your reputation as well as your family reputation if you decide to do otherwise. It may be that she "glances" at other men as well, but at least it won't be you who does the deed.
It's not cheap to bring a wife over to the states, and most of us know what's involved in traditional Hmong marriages so there's alot of sacrifice and effort that feels thrown out when adultery is committed in any marriage. I've seen plenty of attractive wives of relatives, but that's all I register in my head: she's pretty, he's lucky, hope the best for them. 
i know he's been looking for the longest time but he's patient and i don't want to be like him either, wait until i'm close to nearly 50 to get hitched.
i treat her as a sister-in-law... and staying far far far away!!!!!
Most of these girls are sick and dirty in the mind, they see a younger man than their husband and they start itching inside. Don't fall prey to them either, unless you want trouble. My point is what two person committing adultry/affair doesn't get into trouble eventually? They all do.
it's going to be difficult seeing her during family functions.
i've got to put a mental block on her.