farhan has a point, many international students especially those who go overseas for undergrad are pretty young, 17-18 years old, so just as they are becoming their own person they are in a different culture. Its not always about money either, its just where they feel more comfortable.
This is just my experience from undergrad. I am not generalizing the entire population. But those young 17-18 year olds that came over for their studies for the most part were super wild. Suddenly they had all this freedom, the amenities, the resources to "become their own person". The guys at my university (and I went to a HUGE school...over 30 thousand undergrad students... a huge chunk were overseas students) were especially all about Indian girls. Overseas Indian girls though. There were not that many paki girls that were studying abroad. But there were a lot of Indian girls. With those girls, they were able to feel comfortable with them due to their similar backgrounds and similar circumstances in their new environment. Indian girls are generally more wild than Paki girls as well (once again...only from my experience at my school). Us paki girls got turned off by this. Beyond the usual concerns about "he's only interested in me for citizenship reasons", there were the usual different upbringings and mentalities, and then the turn off about how wild some of these guys got and how close they became with their Indian overseas chicas.
True story: An overseas paki guy at my school married a gori. For citizenship reasons. But he paid her. He did not have that much money obvi being a student and only having a part time job. So all of his buddies helped him out by pitching in. It was just another turn off....like ok..cant believe that guy did that..and can't believe his buddies are supporting him.
I heard the guy's divorced now.
Stories like these just make girls here skeptical.