I'm not sure why RKO Pictures entitled this film Affair With A Stranger since what it is is the story of two married people played by Victor Mature and Jean Simmons. It's told from the point of view of their friends who read about it in the Broadway gossip column of Henny Backus and the influence of that other RKO classic Citizen Kane is unmistakable.
Mature is a likable enough fellow who is an aspiring playwright on Broadway who likes to gamble and have a good time as well and Simmons is a girl who nurtures him until he gains success. But then being a Broadway success he falls prey to the usual temptations. A really big temptation comes his way in the form of his latest leading lady, husband collecting Monica Lewis.
The cast has some real scene stealing character players like George Cleveland, Jane Darwell, Wally Vernon and Dabbs Greer all of whom are part of the lives of Simmons and Mature. They form a real rooting section for this marriage and they all care about the two leads and make you care as well. The story is told mostly through their recollections of how the relationship of Mature and Simmons has developed over the years and you get to know them as good if flawed people, especially Mature.
It's not Citizen Kane hardly, but Affair With A Stranger is a good entertaining drama with a great cast even if the title of the film was probably done to sensationalize the film a bit and get folks to plunk down their money thinking it might be something else. It's good enough as it is, on its own merits.