Perhaps because "Three Into Two Won't Go" was written by a woman (Edna O'Brien), based upon Andrea Newman's novel, it has a distinctly (and cuttingly) female point of view on the after-effects of an extra-marital affair. 43-year-old advertising executive in England is unhappily married to a former teacher; she's anxious over the pricey new home they've bought, and unhappy that she and her husband can't have children (and that he isn't enthusiastic about adoption). He picks up a comely hitchhiker one morning and unassumingly checks into a hotel room with her, but after a second tryst the young woman shows up on his doorstep and befriends the Mrs. Complex character-study begins with some frisky interplay, yet in the second-half becomes a sobering drama of tangled lives. Rod Steiger is so engaging when he's playing a randy sort that it's a bit of a let-down to see the scenario turn into an elongated marital complication (with the scheming hitchhiker pregnant/not pregnant). Still, Rod is wonderful trying to sort out the prickly emotions and feelings of both his wife and his mistress, and both women are intriguing, three-dimensional characters. For those expecting a sexy comedy, the pointed shift toward melodrama won't be a satisfying turn. However, this change in tone does allow for several truths about marriage (and in-laws) to come to the fore, and the final confrontation is downbeat but extremely well-considered. A smart, adult movie about decent people making questionable choices, and how those decisions touch everyone else. **1/2 from ****