Bob & Carol & Ted & Alice (1969)

Bob & Carol & Ted & Alice, focuses on the intersecting lives of the titular foursome, giving a bittersweet comedic take on the growing tensions of two "groovy" couples as they grow together and apart in different ways during the sexual revolution of the late 60s.  Like the key parties of the time, this foursome has plenty of sexual tension bubbling over as they admit to affairs and attractions throughout the movie, choosing sides with pithy dialog pitting couple and lover against one another throughout!  This 1969 film racked up 4 Academy Award nominations including Best Supporting actor for sexy Jewish icon, Elliott Gould who goes shirtless in several scenes with wife Dyan Cannon.  The sexy and slightly older Robert Culp gives us the more revealing material in this one though, showing a bulge that'll make you remember a simpler time when revealing bulges were about as racy as cinema got!