A love triangle (also called a romantic love triangle or a romance triangle) is usually a romantic relationship involving three people. While it can refer to two people independently romantically linked with a third, it usually implies that each of the three people has some kind of relationship to the other two. The relationships can be friendships, romantic, or familial.
The 1994 book Beliefs, Reasoning, and Decision Making states, "Although the romantic love triangle is formally identical to the friendship triad, as many have noted their actual implications are quite different....Romantic love is typically viewed as an exclusive relationship, whereas friendship is not." Statistics suggest that, in Western society, "willingly or not, most adults have been involved in a love triangle".
Two main forms of love triangle have been distinguished: "there is the rivalrous triangle, where the lover is competing with a rival for the love of the beloved, and the split-object triangle, where a lover has split their attention between two love objects".
The term "love triangle" generally connotes an arrangement unsuitable to one or more of the people involved. One person typically ends up feeling betrayed at some point (e.g., "Person A is jealous of Person C who is having a relationship with Person B who, in Person A's eyes, is 'his/her' person."). A similar arrangement that is agreed upon by all parties is sometimes called a triad, which is a type of polyamory even though polyamory usually implies sexual relations. Within the context of monogamy, love triangles are inherently unstable, with unrequited love and jealousy as common themes. In most cases, the jealous or rejected first party ends a friendship—and sometimes even starts a fight with—the second party over the third-party love interest. Though rare, love triangles have been known to lead to murder or suicide committed by the actual or perceived rejected lover.
Psychoanalysis has explored 'the theme of erotic love triangles and their roots in the Oedipal triangle'. Experience suggests that 'a repeated pattern of forming or being caught in love triangle can be much dissolved by beginning to analyse the patterns of the childhood relationship to each parent in turn and to both parents as a couple'. In such instances, 'you find men who are attracted only by married woman but who can't sustain the relationship if it threatens to become more than an affair. They need the husband to protect them from a full relationship...as women who repeatedly get involved with married men need the wives'.