You cant. Let someone else in and a different connection is made. During sex, Oxytocin is released in both the man and the woman. Oxytocin is highly bonding. If either the man or the woman have sex with someone else, they will bond with them its that simple. Oxytocin is effective known as the love hormone.
Break the cycle by having sex with someone else, and love diminishes. So no its not possible, its actually contradictory.