In my counseling practice, I often point people to one of two resources:

How We Love (2017 expanded edition) and new How We Love Workbook, by Milan and Kay Yerkovich. They are a couple who lead marriage seminars to train couples to understand the "Love Styles" -- what I call Attachment Styles -- of their partner and themselves so they can learn to appreciate each other better, handle conflict better, and love each other more fully.
Getting the Love You Want, by Harville Hendrix (20th Anniversary Edition). Hendrix has been around longer than the Yerkoviches, and their "Imago" exercises are classic. I frequently use the Relationship Vision and Imago Workup with my couples. Partners where one or both identify in the sexual minority realm would prefer this book.

These aren't the only two sources I glean from, but my own communications training with couples doesn't stray far from these trainers.

So here we go! Let's learn about listening!

LESSON ONE – Hearing

LESSON TWO – Understanding