Three To Get Married–Fulton Sheen. An oldie but a goodie!
A Lasting Promise–Scott Stanley. This isn’t a Catholic book per se–it’s Christian–but it has a LOT of good advice in there about communication. I can’t remember offhand if there’s anything in there that’s opposed to the Faith; I seem to recall a mention of discussing birth control prior to marriage, but I could be mistaken. In any case, use what you can (i.e., the suggestions on how to communicate effectively) and ignore anything that isn’t applicable for your marriage.
The Five Love Languages–Gary Chapman. This is a very “hyped” book, but with good reason. Being able to discuss the best ways to give and receive affection will really help your marriage, and, eventually, your family when you have kids.
For Better…Forever–Greg Popcak. Popcak is a Catholic therapist. I found his style to be mildly annoying at times, but he did have a lot of very good suggestions, and the style thing is a question of personal preference, not of theological difference or anything. He also wrote a book about Catholic sexuality called Holy Sex, but I haven’t read it so I can’t really comment on it.
Hope that helps!