Good Against Evil (1977)

Dack Rambo and Elyssa Davalos star as sweethearts Andy Stuart and Jessica Gordon. The course of true love is messed up when Satan claims Jessica as his own personal property. Desperately, Andy turns to a pair of priests, Fathers Kemschler and Wheatley, for spiritual guidance, not to mention a bit of brute force in purging poor Jessica of her demons.