Not long ago, Brandon Perlberg had a growing law practice and a Manhattan apartment he shared with his partner, who is British. They hosted themed dinner parties and wine tastings for a wide circle of friends.
But Mr. Perlberg, an American who is gay, now lives in London. Early last year he reluctantly left his law firm, rented out his apartment and said goodbye to friends. After nearly seven years in the United States on legal but temporary visas, his partner had not been able to obtain a visa as a permanent resident. The two were facing the possibility of permanent separation.