A movie from the 80ies or early 90ies about a woman that turns into a ninja by night. She is unconscious of whatever goes on while she is transformed, as if taken over by an evil spirit. She would often return home and wake up the next morning with bruises etc.. Her boyfrd or husband starts to suspect something is going on behind his back and then either him or someone else defeats her... well something like that anyway.. so does it ring a bell?

Ninja III: The Domination (1984)