I can think of no other universal reference & resource than Harville Hendrix’s seminal work, “Getting the Love You Want: A Guide for Couples” written when Dr. Hendrix was a lowly master’s level counselor yet was the seasoned master in Couples Therapy in 1988.
Buy this book. Read it once or twice. Certain technical passages require extra effort to understand Harville’s Imago Therapy. And do the exercises at the end of the book.
I would not bother with any of the offshoots, i.e. the subsequent books and workbooks. Hendrix’s original tome has the power.