There are no couples that are not tested. This is the natural order of this testing realm we refer to as life. All couples will be tested by their relationship with each other, and by their children or childlessness, with good health or poor, with wealth or hardship.
Every couple must expect to be tested; there is no perfect, harmonious relationship, devoid of adversity. The only thing that sets some apart from others is how they deal with the trials of life. For some, the virtue of rida (contentment) is at play; for others, rahma (mercy).
Some, when faced with misfortune, fall apart; others fall further in love. It’s a state of mind, and a choice.