OTHER REAL SEX MOVIES?
Not porn.
shareBatalla en el cielo (2005)
Fingered (1986 Short Film)
The French keep TRYING to do this ("Baise Moi", "Sexual Chronicles of a French Family"), but it doesn't seem to work well. Your best male actors aren't necessarily able to have sex in public and a lot of the guys that can have all the raw acting talent of Ron Jeremy or James Deen.
A lot of young American actresses meanwhile make a big frickin' deal of doing nude scenes, let alone porn, but even the best French and European actresses have stayed well away from on-screen sex. Chloe Sevigny probably hasn't helped this cause by doing what she did in such a godawful movie.
Actually, the most interesting example is Asia Argento with "Scarlet Diva", who claimed that she and her actors had real sex even though she didn't verify this by showing the penetration. Strangely, the movie was also produced by her own uncle and co-starred her own mother. . .