I am looking for the title of an old movie, I believe its from around the 60s or 70s, all I remember is the basic plot which involves a young guy dating 3 different girls at the same time without them knowing, eventually the girls all find out about each other and plot revenge on the guy by tying him up (in an attic I think) and taking turns having sex with him all day every day without break, until eventually after a little while (weeks or months) he is too week to move and appears to have aged significantly which was the girls plan.

Maybe, "What a Way to Go"!

Maybe, "What a Way to Go"!

No, I looked up both movies of that title and although one is similar its not the one I'm looking for, but thanks anyway.

Three in the Attic (1968) (http://www.imdb.com/title/tt0063693/)

Three in the Attic (1968) (http://www.imdb.com/title/tt0063693/)

Yeah that sounds like the one, thanks.

You're welcome.