home invader 

A person who hooks up with someone who is in a relationship but does not want to break them up or have a romantic relationship with that person. Like a home wrecker only without trying to mess up the home, they just want to get it in for themselves.

Nahh, I'm just a home invader! He can keep his girlfriend I just want to get it in on the side!

home invader by nikkiibee13 April 1, 2011