The movie I'm looking for was on in the 80's and it was a horror flick. The only thing I remember about it was the way it started. An older mom and her teenage daughter live in this house. The mom's boyfriend seduces the daughter who rejects him at first, but gives in after coming home late from a party one night. She's in the kitchen getting something out of the fridge and he makes his move. The mom peaks into her daughters room and catches him having sex with her daughter. When he opens the door to leave her room the mom stabs him and the movie begins. The title is right there at that point but I can't remember it.

I have no idea but if you can remember any of the actors names or songs that were played in the movie, then you can check for the title that way on imdb.com