or social group, rejecting all others; in contrast to exogamy. Hypergamy – act or practice of seeking a spouse of higher socioeconomic status, or caste status than oneself; in contrast to hypogamy. Sexual relations Human sexual activity – Sexual intercourse – Swinging – Dysfunctional relations Dysfunctional family – Relational transgression – violation of implicit or explicit relational rules. Abusive relations Abuse Child abuse Elder abuse Dating abuse Domestic violence Emotional abuse Verbal abuse Gaslighting Financial abuse Infidelity – breach of the expectation of sexual exclusivity. Also called "cheating". Extramarital affair Adultery Extramarital sex Neglect Spousal abuse End of a relationship Breaking up – Divorce – Legal separation – Widowhood – Reasons for ending a relationship Dysfunctional relations – see Dysfunctional relations section above. Irreconcilable differences – Relational transgression – violation of implicit or explicit relational rules. Theories of interpersonal relations Socionics – theory of intertype relations incorporating Carl Jung's work on personality types with Antoni Kępiński's theory of information metabolism. Attachment theory – describes the dynamics of long-term relationships between humans. Its most important tenet is that an infant needs to develop a relationship with at least one primary caregiver for social and emotional development to occur normally. Social exchange theory – a social-psychological and sociological perspective that explains social change and stability as a process of negotiated exchanges between parties. Posits that human relationships are formed by a subjective cost-benefit analysis and the comparison of alternatives. Relational models theory – a psychological theory authored by Alan Fiske proposing four elementary forms of human relations. Relationship characteristics Aspects of relationships include: Attachment in adults – Attachment in children – Interpersonal attraction – force acting between two people that tends to draw them together and resist their separation, which leads to friendships and romantic relationships. It is distinct from physical attraction. New relationship energy (NRE) – state of mind experienced at the beginning of most significant sexual and romantic relationships, typically involving heightened emotional and sexual receptivity and excitement. Stages of a relationship Stages presented in George Levinger's relationship model: Acquaintance Buildup Continuation Deterioration Termination Feelings and emotions Love Familial love Parental love Marital love Brotherly love Filial piety Veneration Romance Infatuation Intimacy Jealousy Limerence Passion Platonic love Psychology of sexual monogamy Unconditional love Sexual orientation Bisexual Heterosexual Homosexual Asexual Pansexual Romantic orientation Aromanticism Homoromanticism Heteroromanticism Biromanticism Panromanticism Relationship partners Terms for partners in intimate relationships include: Boyfriend/Girlfriend Confidant or confidante