Jealousy
From Memory Alpha, the free Star Trek reference
Jealousy is an emotion that refers to the thoughts, feelings, and behaviors that occur when a person believes a valued relationship is being threatened by a rival.
In order to free himself and his crew from the Kelvans, Captain James T. Kirk aroused feelings of jealousy in the as-yet emotionally immature aliens – Kirk caused Rojan to become jealous by seducing Kelinda. (TOS: "By Any Other Name")
