If you are going around thinking, Well, I deserve a better person or she needs to go to someone else to understand my worth! then your marriage is in trouble. It also yells trouble if you want to have an affair. There is a gaping hole in the marriage that needs to be fixed right away. Talk about this right away and avoid procrastinating.
If you are asking the question your marriage is probably already in rough shape. That said, partners in a floundering marriage often do not have the insight to recognize the relational trouble until the situation becomes quite caustic. A neutral party – ideally a therapist or clergyperson – can visit with the couple and help probe the relationship’s health. Further, if other couples and friends who are close to the couple begin asking questions about the relationship’s health, one may assume that there may be some trouble. Listen to friends and family when they voice concern, and be willing to take proactive steps to address the marital trouble.