Twist ending but that's all i got

[Seenit]

I walked in at the end of this movie.  The movie is at the very latest from the late 80's, however I think it is from the 90s.  The movie is in color, but at the end a man is watching a projection (?) film or home movie made in black and white.  The scene takes place in a bedroom, possibly his own.  His wife is bed with a man while in the background, I believe they are standing outside the window, the people of the town are quietly watching. (creepy!)  His wife gets out a knife and begins stabbing the man in the back. Somewhere in this film the man making love to his wife turns around to reveal its the man watching the film.  He's already dead.  Someone in a different search suggested that it might be a a 70s movie called "Dead and Buried".  It might be, they certainly have some common elements, but I don't think this is the film.  This movie looks dated, very grainy.  The clothes I remember seem closer to early to mid 90s. One other thing the people watching in the window appeared to have a vacant look.  I don't know if this is because they were zombies, evil, aliens, or vampires.  I don't have a lot to go with.  Searches have not turned up anything.  Hope someone has seen this one.  Thank you!

[Rayo Casablanca]

DEAD AND BURIED is a very good guess. It's from the early 80s and the town's full of reanimated corpses. I might be wrong but I believe there is a scene just as you describe at the end.