Friend of mine had a younger sister who was really into the whole social consciousness schtick. She ended up in the Peace Corps in the Central African Republic for a couple of years, and ended up falling in love with a guy, whom she brought back with her. Took a long time to get everything cleared, she paid all of the bills because it was expensive.
Within 6 months of them getting back to the United States... he takes off with his green card. It's all he wanted.
Only... he figured she was still going to be the cash cow, and he did his damndest to milk it. Her brother, my friend, had to step in in no uncertain terms.