I put Disciplines of a Godly Man on the list even though I have not read it, mostly because I am not its primary audience. Hughes frames spiritual discipline as a response to grace rather than a way to earn God’s favor and applies that idea across relationships, prayer, worship, integrity, work, leadership, giving, witness, and ministry.
It is the companion to Disciplines of a Godly Woman, and I think the pair could be valuable to read together as a couple. If spiritual formation is something you want to pursue intentionally in your marriage, this might be one of those “buy both and compare notes” kinds of reads.