Model K.T. Mary Dunphy alleges in a lawsuit filed in Suffolk County (N.Y.) Supreme Court that her former fiance, Robert Oppenheimer Jr., cheated on her with Dupre while she was pregnant last year, the New York Daily News reported Saturday.
Dunphy alleges she found her fiance having sex with the reputed call girl during the summer of that year.
The 41-year-old model alleges Oppenheimer caused her "emotional distress" and that Oppenheimer, 55, routinely used drugs and cheated on her with other women during their relationship.
Dunphy also alleges after Oppenheimer attempted to evict her from a home in Southampton, N.Y., she miscarried.
A spokeswoman for Dupre told the Daily News that Dupre denies knowing Oppenheimer and never spent time with him in Aruba as Dunphy alleges.
"She doesn't know anyone named Robert Oppenheimer and has never been to Aruba," the unidentified spokeswoman said.
Celebrity Families of 2014 [PHOTOS]