Wendigo (2001)

What is meant to be a fun, relaxing trip to the country goes very wrong in the horror flick Wendigo (2001). George (Jake Weber) is a photographer who is very stressed out about his high pressure job working for a New York ad agency. He and his wife decide to head to upstate New York with their son for a little vacation. They can enjoy the peace and quiet and have fun in the snow. When they arrive, however, they discover that the place they are staying in may be haunted by a mythical beast set on tearing them limb from limb.

In the cabin Jake and his wife get their freak on in front of the fireplace. We see him shirtless as the action starts then eventually we get some nice sidage and bare ass shots as he thrusts away while some creepy dude peeks in the window and watches them.