The Truthful Sex (1926)

Sally Mapes and her husband Robert have a glorious romance after they are married, but they hit trouble after their son is born: Robert thinks that Sally cares more for their son than she does for him, and he just drifts along with his club-and-society activities, while Sally thinks he no longer loves her. She is attracted by Paul Gregg, one of society's useless members, which leads her and Robert to argue, and Robert departs. Jennie, the baby's governess, has an affair with a crook named Barnes, and one night while Barnes comes to rob the apartment he hears Paul imploring Sally to run away with him. And one thing leads to another.