Romantic partners in the Psy-Changeling universe are able to form permanent mental bonds with each other. These bonds change slightly depending on the races of the participants.
In pairings involving Changelings
For couples where one or both is changeling, the process of recognising and forming a psychic bond with a mate is referred to as the mating dance. In this males will recognise that a person (changeling, human or psy), is their mate and females will decide whether to allow a psychic bond to form. Both parties can choose to block this process if they wish, as shown in Tangle of need.
In parings involving Psy
In pairings where both are psy, they fall in love and consciously or unconsciously allow a psychic bond to form when the relationship becomes permanent. In pairings where only one is psy and the other is human, a purely subconscious psychic link appears to form, as described with Max and Sophia from Alligance of honor onwards.