Quarrels in marriage

Arguments are inseparable from relationships. But when is it still a necessary "spice of love" and when are disputes a signal of an impending crisis? This may not be obvious at first glance to either party. Why is it that one marriage is happy, even though it is a typical "Italian household", and another is heading for ruin, even though the couple hardly argue? Is there any proven way to avoid the impending conflict? What are the most common mistakes we make in these situations? A book by a well-known Czech psychologist, which deals with the topic of conflict situations, quarrels and crises in marriage, may be a hint.