Happy Though Married is a 1919 American silent comedy film directed by Fred Niblo.
The brothers own a mining claim that Diana's uncle (French) wants to buy, so Jim stays in Mexico to look after the property while Stanley goes to New York to try to obtain a better price.
There he discovers Bob Davis (McCullough) is trying to cut him out, so he marries Millicent without delay.
As a joke he buys his wife a book titled How to be Happy Though Married, but it ends up giving her jealous thoughts.
She finds the photograph of Diana in Stanley's coat pocket and pretends to go away on a visit, but when she returns to the house she finds her husband escorting the original from the photograph and installing her in one of the bedrooms.