Blood Bride (1980)

Thirty-something devoted Catholic Marie isn't getting any younger and her father is pressuring her to find a husband. She works as a secretary for Henry Stern and she falls for one of his clients - the charming, good looking and a bit older antique book dealer John McPherson. Despite his traumatic childhood and her sexual repression, they hit it off and he soon proposes marriage. She's delighted, although her parents are a bit worried since she barely knows him. It soon turns out that John does indeed have a dark violent secret tied to his traumatic first sexual experience as a very young boy, which led to his lifelong sadomasochistic obsession with Sister Marry, a beautiful diabolical nun he once knew as a child. The disturbing memories of her have been haunting him ever since and now he looks for women who look like her to hurt them. And unsuspecting Marie is a dead ringer for her. However, John is about to realize that Sister Marry is not who he thinks she is.