First, realize that the stimilus bill, when enacted, amended the existing tax credit for first-time homebuyers -- it is not 'new' law. The parts of the law not amended stay the same. Thus, as stated in the original law, if married, both spouses must be on the new deed in order to claim the credit. Therefore, BOTH spouses must be first-time homebuyers (or not owned a residence in the previous three years). So, it looks like your fiance can only claim the credit if she buys, by herself, before you are married.