Kleptoromantic 

A person who does not see another person as a romantic or sexual partner until they become unavailable. Who then tries to steal them away no matter what.

Brent: Man I didn't realize how hot Tiffany was until she started dating Mike. I think I need to get her back to my place.
Dave: Dude you are such a kleptoromantic, just leave it be.

Kleptoromantic by FreeshAvocadoo July 29, 2019

Kleptoromantic 

A person who can only feel romantic attraction to someone they stole from other potential suitors/existing partners or who stole them from other potential suitors/existing partners. The sexual counterpart to kleptoromantic is kleptosexual.

Bob is telling Joe about a girl he is romantically interested in. Joe does not seem interested in this particular girl at first but when the girl starts flirting with Joe, he suddenly feels romantic attraction to her merely out of knowing that Bob wanted her first and that he would essentially be "stealing" her from him if he were to pursue her (assume that Joe's feelings for her are genuine and that he isn't just pursuing her to mess with Bob). This would make Joe a kleptoromantic.

An example of a kleptoromantic in popular media is Lilly from the film "Alpha and Omega" (2010).

Kleptoromantic by wackywolfao August 27, 2021