Intimate relationships exist in social domains, in which there are cultural rules regarding appropriate behaviors. But they also inhabit psychological domains of thoughts, feelings, and desires. How are intimate relationships experienced by people living in various types of romantic or sexual relationships and in various cultural regions around the world? In what ways are they similar, and in what ways are they different? This book presents a cross-cultural extension of the findings originating from the classic Boston Couples Study. Amassing a wealth of new data from almost 9,000 participants worldwide, Hill explores the factors that predict having a current partner, relationship satisfaction, and relationship commitment. These predictions are compared across eight relationship types and nine cultural regions, then uniquely combined in a Comprehensive Partner Model and a Comprehensive Commitment Model. The findings test the generalizability of previous theories about intimate relationships, with implications for self-reflection, couples counseling, and well-being.