A closed marriage is any marriage that is monogamous with no emotional intimacy or sexual behavior of any kind occurring outside of the marriage. This is what many people consider the "standard" or "typical" form of marriage. It is comprised of two partners who practice complete fidelity to one another.
More About Closed Marriage
Closed marriages are the most common form of marriage in most western countries, existing in contrast to open marriages which many people still consider taboo or risque. Using the term "closed marriage" to describe this kind of marriage is an important step in recognizing that there is not necessarily a "right" way to be married. Open marriages aren't the "other." There are simply different forms marriage can take.