The pros of introducing a third person into a relationship are that it can add an element of excitement and variety to the relationship. It can also provide an opportunity for couples to explore their sexuality in new ways, such as through exploration of different sexual activities or fantasies. Bringing a third person into the mix may help to bring balance to a relationship if one partner feels neglected or not fully appreciated by the other. On the other hand, introducing a third person into a relationship can also bring about negative consequences.