And that's when things begin to unravel.
While I was watching the movie, I was reminded of another film, 1967's Two for the Road, directed by Stanley Donen, written by Frederick Raphael (Darling, Eyes Wide Shut), and starring Audrey Hepburn and Albert Finney. I had just seen it again on the Fox Movie Channel a couple of weeks ago, and enjoyed it immensely (my wife, on the other hand, hated it).
While both films deal with marital difficulties, and contain many parallels, they reach entirely different conclusions. While I won't give away the ending of Revolutionary Road, I will say that Two for the Road is ultimately much more an affirmation of marriage. The love between Mark and Joanna Wallace, unlike Frank and April Wheeler's, ultimately keeps them together, because they need each other and genuinely care for one another, despite all the fights and tit-for-tat infidelities.
I recommend both films highly, although Two for the Road is definitely the better date movie for marrieds; Revolutionary Road is best seen without your spouse.