Yesterday we celebrated Christ's Resurrection from the dead. He died for us. He was the perfect sacrifice. He who was without sin endured the cross for our sins. We did not deserve to receive the grace He showed us, but His love for us was so great that He took our sins on Himself so that we may enjoy eternal life.
When we consider the tremendous grace that God has shown us, how can we not in turn show grace to our spouse? We are all sinners. We all mess up and sometimes mess up big, but it will never be so much that we can't show grace.
The book of Hosea is a great example. Hosea was called to marry and love Gomer, a woman who was consistently unfaithful. In the end, Gomer came to realize what she was doing and sought forgiveness. God asked Hosea to do this as an example of His love for His people. We should be able to forgive even unfaithfulness just as God forgives our unfaithfulness to Him.
John 1:16 And of his fulness have all we received, and grace for grace.