The basic premise of this movie centers around a couple who has been married for 25+ years and the subtle issues that arise during their marriage. Essentially, the wife wants her husband and herself to go to therapy so they can work on their marriage, but he does not feel there is anything to work on in their marriage.
Marriage is just like any relationship, except a marriage entails a contractual relationship where a “break up” is called a divorce or a separation. Marriage is also unique because there is a physical, emotional, mental, and friendship connection, and when one of the elements are missing the relationship will have issues; sometimes those issues will manifest into bigger problems.
The bottom line is if you are married BOTH parties have to WORK on the relationship and if BOTH parties do not WORK on the marriage it will go down a dark and sad road that may or may not lead to divorce.