The idle rich have little to occupy their time but playing cards and seducing each other's spouses. At least that is what the characters in "This Man is Mine" suggest. This short tired tale of marital infidelity, adapted from a play, retains its staginess and does not merit the presence of Irene Dunne in the central role. Despite her talent and beauty and voice, Dunne as Tony Dunlap fails to convince viewers that her character would try to save a worthless marriage to Jim Dunlap, played by Ralph Bellamy. Bellamy evidently has retained suppressed feelings for a former flame throughout his marriage to Dunne, with whom he has had a young son. When the former girlfriend arrives on the scene to rekindle her romance with Bellamy, the film's fragile grip on credibility crumbles. Although Constance Cummings as Francesca is an amusing conniving tart, the transparency of her character and motives makes Bellamy look like an utter idiot when he returns her advances. Viewers may be forgiven for shouting "you blithering fool" and throwing tomatoes at the screen when Bellamy falls for Cummings's tricks, especially when the other characters on screen easily see through her. Bellamy's character must have inherited wealth, because there was no way this gullible dimwit could make his way in the business world. As a father, he is ready to toss away his child for a shallow man hunter. He does not deserve Irene Dunne's attention, let alone her hand and devotion. By the final frame, "This Man is Mine" has descended into completely incredible nonsense. Only the performances of Dunne and Cummings and the handsome presence of future western star Charles Starrett offer any reason to see this annoying trifle.