In my book, Like Yourselves and Others Will Too (Prentice-Hall 1978), I described a phenomenon called "New House Disease." When a couple, whose children have all married and moved out, acquire a beautiful new home or condominium and move into it, the marriage is in danger of falling apart.
What happened? Differences that had arisen between the couple were never confronted and resolved. Rather, they were glossed over and covered up, much as one might conceal a defect in the wall with wallpaper. Unresolved conflicts may give rise to resentments, which feed upon themselves and increase in intensity. (It is even possible that a particular resentment persists after the incident that caused it has been forgotten, and now the spouse retains the resentment without knowing why.) Since resentment is likely to result in guilt, the psychological defense mechanism now justifies the resentment by projecting it onto something else - the house. They reassure each other: "Nothing is really wrong between the two of us. We are having difficulties because we are living in this inadequate house. If we had a more spacious house with the necessary conveniences, every thing would be okay."
If after moving into the new house, the couple discovers that things are not okay, they now have lost their last excuse to explain away their unhappiness and must come face to face with the unresolved conflict. This shock alone may terminate the relationship.