A backronym for FAP. Usually associated with putting something in the spank bank,
I'll need to see the source... for Federally Associated Purposes of course.
The Purposeful Expendable Boyfriend is a job a boy or man plays to make sure the newly broken up with girl isn't talked into having any sort of sexual interaction with a person she will regret it with during the " Broken Heart " phase of after breaking up with someone. Or even breaking up with someone she really cares about during an already fragile phase.
" Why aren't you mad or sad? I just broke up with you?? " " Don't you see? I'm being a PEB - Purposeful Expendable Boyfriend. To make sure no one gets to you and you don't have to breakup with someone who you care about. "