For the foundations of Western ideas about marriage (most of which were formulated in the Middle Ages out of a mixture of Roman law, Christianity, and Germanic and Celtic law and customs), try:

• How Marriage Became One of the Sacraments: The Sacramental Theology of Marriage from its Medieval Origins to the Council of Trent by Philip L. Reynolds
• The Knight, the Lady, and the Priest: The Making of Modern Marriage in Medieval France by Georges Duby
• Law, Sex, and Christian Society in Medieval Europe by James Brundage
• Marriage and the Family in the Middle Ages by Frances and Joseph Gies

The Gieses' book is the best to start with, because it's aimed at laymen rather than scholars.

For a read about the shift from arranged marriage to companionate marriage based on romantic love came about, try Marriage, a History: From Obedience to Intimacy, or How Love Conquered Marriage by Stephanie Coontz.