Every marriage has its own set of problems. Some couples deal with constant fighting, money problems, or infidelity. Other couples face the heavier burden of losing a child, having difficulty conceiving, or maybe even a life-changing illness. Whatever the issue, God can help husbands and wives overcome the difficulties that are affecting their union.

Christian writer Meg Wallace has witnessed marriages that have been destroyed by infidelity, but she has also seen couples triumph over it. Wallace noticed that there is one common denominator in all failed marriages - a hardness of heart.

"Hardness of heart is lacking genuine sorrow over sin, continuing to go back again and again into temptation, lies and deceit, [and] choosing to think of yourself as most important," she wrote for Faith Wire.

She added that a hardened heart is unteachable and selfish, and it is driven by lies - both small and big - that are being burshed aside as "not a big deal." The list is lengthy, and Wallace said that couples need to guard their hearts with due diligence in order for their marriages to thrive.

"It has no place in marriage, yet in big ways and in small ways we let it creep in. This hardness often begins so subtly, with the smallest acts of selfishness...but left unchecked can grow to become a raging fire of wrath, anger, hatred and bitterness," she warned.

Wallace stressed that marriage takes work, but it goes beyond the occasional act of service such as helping with the chores or surprise treats. "I'm talking about grueling, gut wrenching, goes-against-everything-you-feel work," she said. "I'm talking about choosing to daily lay down your life for another, looking for ways to love, to pursue, and being relentless to leave no room for distance."

Meanwhile, Billy Graham's daughter Ruth, who also dealt with heartbreak and divorce, told CBN News that forgiveness is another issue that many couples struggle with. As challenging as it might be to forgive someone, Ruth strongly encouraged people to do so for their own sake.

"You make the decision to forgive, and everything in you will scream, 'No! This isn't fair. I'm not going to do it!' But forgiveness doesn't mean forgetting or taking away the consequences or acting like something never happened," she explained. "Forgiveness is very realistic, and it looks the offense in the eye and calls it for what it is. And it doesn't really let the other person off the hook; it lets you off the hook."