Common Law Wife (1961)

You don't have to say

Shug, a rich old man, throws out his longtime live-in mistress and moves in his young, sexy niece, who's just returned home after making a living as a stripper in New Orleans. The mistress doesn't intend to go without a fight, however, and while Shug tries to make peace between the two women, he doesn't realize that his niece has her own plans for him.