Marriage and relationships

Marriage is the social institution in which two (or, less frequently, more) people commit themselves to a socially sanctioned relationship in which sexual intercourse is legitimated and there is legally recognized responsibility for any offspring as well as for each other. Although there are exceptions, the marital partners typically live together in the same residence.

A relationship is a continuing and often committed association between two or more people, as in a family, friendship, marriage, partnership, or other interpersonal link in which the participants have some degree of influence on each other’s thoughts, feelings, and actions. In psychotherapy, the therapist–patient relationship is thought to be an essential aspect of patient improvement. 

Adapted from the APA Dictionary of Psychology