Let him know that his parents love and respect each other.Teach him important values in life and show him how important it is to follow them.Lack of empathy in a marriage can often reflect in children. But barring these exceptions, children do pick up the same things and behave in an unsympathetic way after watching their parents.
Moreover, whenever they do try to talk, they are mostly tired and irritable. As time passes, the expression of feelings for each other also reduces, ultimately leading to a situation where neither individual sympathizes with the other.
Thus, leading to a complete breakdown in communication and trouble in the relationship.
The best solution in this case is a second honeymoon.
The concept of a honeymoon vacation is basically to allow the couple to bond with each other; physically, mentally and emotionally.
They tend to view life pragmatically, where "what is, is! More so, they may even use this knowledge to manipulate the person.