HouseSitter (1992)

Plot:

When his longtime girlfriend Becky says no to marriage and the house he has built, architect Newton Davis takes it badly. Three months later a one night liaison with livewire waitress Gwen gets rather out of control when she tracks down the dream house, moves in, and lets it be known locally that she and Newton are married. Everyone in the small town take to her, including his parents, while Becky shows renewed interest. When Newton realises the situation he suggests to Gwen that continuing the deception might have advantages for both of them.