I've found that "Love in the Present Tense" by Morrie and Arleah Shechtman is a terrific book on relationships. These authors, too, challenge some conventional myths about love and marriage with provocative insights. The book is concise and clearly written. Highly recommended.

As a psychotherapist who specializes in couples and as a coach who works with singles on relationship issues,I often recommend John Gottman to others; he is the leading researcher in the field today.
One of his many concepts worth sharing is that of the "emotional bank account." He suggests that we look at our interactions with our significant other as deposits or debits into some master "bank account." When you thank your husband for changing the oil in your car or praise your wife for her smart advice on some matter, that's making a deposit; when you criticize your partner or respond to him or her with sarcasm, that's a withdrawal.
Gottman says that to have a "good" marriage, you need to be making far more deposits than withdrawals!