Unicorn Hunter 

A (usually married) m+f couple seeking out a third. They will insist the potential third must be a natal female, and preferably young, pretty, bisexual, and interested in sex with both partners. By the time you've listed all of that, you're looking for a person that's so rare and highly sought-after that, "you're looking for unicorns."

Advertisement: "We're a m+f couple looking for a third! Must be a a cis female, aged 18-25 years old, pretty, submissive, and unlikely to get attached. Bonus if she's willing to act as the an unpaid babysitter and housekeeper. Please send picture and a message telling us why we should choose you."
Person reading the ad: "OK, so you're a unicorn hunter. Sure, those girls are out there, but the chance of finding one is so low that you might as well be hunting for unicorns."

Unicorn Hunter by PinkKitten420 March 19, 2021

Unicorn Hunter 

Derogatory. An individual or couple seeking a unicorn or HBB. Different from a person who is merely attracted to bisexual poly people. Refers to someone who is seeking "that special third to complete" their family. They often believe a bisexual third partner will prevent jealous feelings on the part of either of the original members of the dyad because of the mistaken assumption that one will not get jealous if one gets to do all the same things as the other and no one ever experiences anything apart from the other half of the primary couple.

This type of couple expects their hypothetical future partner to be single or willing to give up any existing and future partners, to love & have sex with both members of the original dyad equally, and for each member of the existing dyad to reciprocate exactly an equal level of love and sexual attraction for the new person.

This type of couple will not consider any kind of relationship with a male, with someone who is only sexually attracted to one of the original dyad members, with someone who is already partnered, & usually promises to break up with the new person for the sake of "protecting" the existing dyad, leaving the unfortunate third partner feeling disposable. Sometimes the unicorn is expected to not develop any emotional attachment and is strictly there for a sexual relationship (equally distributed to both members of the dyad) and/or is prescripted as a secondary.

John is so insecure about sharing his wife with another person, that he thinks he won't ever feel jealous as long as his wife never does anything with anyone else without him also participating so he's looking for a hot bi babe that'll be willing to share them both equally and not make any waves. He's such a unicorn hunter!

Unicorn Hunter by Joreth April 8, 2010

Unicorn Hunters 

A couple who seeks an unattached bi-curious or bi-sexual woman to join them in a threesome.

Bob and Mary explained that they were unicorn hunters to a woman at a bar with hopes she would join them.

Unicorn Hunters by lordofthighs September 18, 2014