Love is unconditional
God demonstrates His own love toward us, in that while we were yet sinners, Christ died for us.
Do something out of the ordinary today for your spouse—something that proves (to you and to them) that your love is based on your choice and nothing else. Wash her car. Clean the kitchen. Buy his favorite dessert. Fold the laundry. Demonstrate love to them for the sheer joy of being their partner in marriage.