Exchange of Partners(1976)

If Variety is the Spice of Life, a Change of Partners is the Spiciest!

Eric and Joelle decided to spend their honeymoon night at the house of a couple of married friends - who happen to be in the midst of a serious marriage crisis. Before sunset, a very young woman arrives riding a motorbike, and says she's Angel. With her strange presence, erotism breaks out, and several couplings and vicious sex erupt in the comfortable home.