Infidelity

Embezzlement is the operative word and it is chosen precisely. Love is a state of semi-permanently open connection through which energy flows, and in a particularly bonded pair such as a monogamous relationship this produces a shared animus, a single pool of life energy that both parties hold. Infidelity takes from that pool to feed something outside it. What makes it embezzlement rather than theft is that the taker has legitimate access, since the energy is genuinely shared, and the diversion happens inside an arrangement built on trust. The mechanism accounts for the observed effects better than betrayal does. The partner who is cheated on becomes stressed and irritable from depletion even where they are unaware of the cause, since the drain does not depend on knowing about it. Their loss of energy then causes them to lose lustre in the eyes of the partner drawing from them, which produces the familiar and otherwise puzzling pattern in which the person being drained becomes less attractive to the person draining them and this is offered as justification. Marsh points out what the cheating partner usually means by insisting they still love the person they are draining, which is that they are unwilling to give up the energy source feeding the new relationship. Her observation that relationships beginning with infidelity usually do not last follows from the same account, since the new relationship was running on borrowed energy that stops arriving.

Infidelity research in psychology studies prevalence, predictors and consequences, treating it as a violation of a relationship agreement and measuring outcomes for trust, depression and relationship survival. Evolutionary psychology has its own accounts through mating strategies and paternity uncertainty. Therapeutic writing, notably Esther Perel's, reframes affairs as expressions of unmet need or of a wish to reconnect with a lost self. All of these locate the harm in the breach of agreement or in what it reveals. Marsh locates it in the diversion of a shared resource, which is why on her account the harm begins before discovery and does not depend on any agreement having been made explicit.