Discipline That Connects With Your Child's Heart, by Jim and Lynne Jackson, is very good, and suitable for those just coming out of a punitive paradigm. They also have a book called
How To Grow A Connected Family
http://connectedfamilies.org/store/
Two books which address general relational dynamics, including marriage:
Keep Your Love On by Danny Silk. He emphasises making connection our goal including during conflict, non controlling communication and setting boundaries.
The High Cost of High Control by Tim Kimmel. Mostly about how to recognise manipulation and control in various forms, useful for FOO issues, has chapters on marriage and parenting (doesn't mention spanking, emphasises things like letting kids make their own decisions, using natural consequences etc.)