I've seen this and I'm sure it's so common to millions around the world. Therapist Dr. Bonnie Weil calls it "Financial Infidelity" in her newest 2009 book. According to her, financial infidelity is the #1 problem in relationships that often leads to lies, betrayal, and affairs. She offers solutions to this pervasive problem by separating the value of the relationship from the bank account.
Jesus said, "You cannot serve both God and money." (Matthew 6:24)