I Will, I Will... for Now is a 1976 film directed by Norman Panama. It stars Elliott Gould and Diane Keaton.
The Binghams weigh the opinions of lawyer Lou, who also has a romantic interest in Katie. Theres also temptation for Les in the form of sexy neighbor Jackie, who gives him a copy of The Joy of Sex as a gift. But as soon as he tries out one of the positions in it, Les throws out his back.The couple takes one last desperate try to revive their passion and save their relationship. They travel to California to join a sextherapy group, where much goes wrong, but all ends well. ........
Source: Wikipedia