Three on a Couch (1966)

Synopsis
Artist Christopher Pride (Jerry Lewis) has just been commissioned to work in Paris. Wanting to kill two birds with one stone, he plans to bring his soon-to-be bride along to celebrate their honeymoon. Unfortunately, his girlfriend (Janet Leigh) is a psychiatrist trying to contend with a trio of young women who utterly despise men. These women are too unstable to leave alone. In hopes of hastening the women's treatment, Christopher impersonates three men in hopes of helping them realize that not all men are cads. ~ Sandra Brennan, All Movie Guide