An intimate relationship is an interpersonal relationship that involves physical and/or emotional intimacy. Physical intimacy is characterized by friendship, platonic love, romantic love, or sexual activity. While the term intimate relationship commonly implies the inclusion of a sexual relationship, the term is also used as a euphemism for a relationship that is strictly sexual. Intimate relationships play a central role in the overall human experience. Humans have a general desire to belong and to love, which is usually satisfied within an intimate relationship. These relationships involve feelings of liking or loving one or more people, romance, physical or sexual attraction, sexual relationships, or emotional and personal support between the members. Intimate relationships allow a social network for people to form strong emotional attachments.

Love is an important factor in physical and emotional intimate relationships. Love is qualitatively and quantitatively different from liking, and the difference is not merely in the presence or absence of sexual attraction. There are three types of love in a relationship: passionate love, companionate love, and sacrificial love. Sacrificial love reflects the subsumption of the individual self will within a union and is said to be expressed within the Christian Godhead and towards humanity. Companionate love involves diminished potent feelings of attachment, an authentic and enduring bond, a sense of mutual commitment, the profound feeling of mutual caring, feeling proud of a mate's accomplishment, and the satisfaction that comes from sharing goals and perspective. In contrast, passionate love is marked by infatuation, intense preoccupation with the partner, throes of ecstasy, and feelings of exhilaration that come from being reunited with the partner.