A precursor to bringing grace to our spouses is understanding them.
Mary Kassian gets this, I think, in a very grace-driven approach to the issue of female beauty (and of wives "letting themselves go").
Not unrelated is understanding the expectations that take place as a marriage grows. Speaking generally, women marry men they love "just as they are," yet with the expectation that they will progress, become more "domesticated," grow in areas of interest and emotion, etc. They expect that the marriage relationship will help their husbands change. Men, on the other hand, generally want the women to stay just as they are. Husbands usually want their wives to resemble twenty years into the marriage the women they were on day one.
Some of the deepest frustrations I've witnessed among married couples occurs when the wife can't believe her husband is essentially the same man he was on the wedding day -- in fact, the things she found appealing or even cute then have now become annoying and sources of hurt -- or when the husband has no idea where this woman who used to be his wife came from.
Men are hard changers. Women are constantly changing and growing.
Spouses need to understand this if they're going to be able to bring grace to the husband who hasn't outgrown his love for college basketball or the wife who once only wanted 1 child but now wants to adopt 20. We are wired differently, and in our cursed-ness this is a recipe for enmity and disaster. But in our gospel blessedness, it is an opportunity for the real love of 1 Corinthians 13.
Steps to Grace-Driven Marriage
Steps to Grace-Driven Sex
A Specified Grace in Solomon's Song