An old flame you can’t help hooking up with periodically, regardless of either person’s relationship status.
Amy: I can’t believe you slept with Adam after the class reunion. He’s engaged and you have a boyfriend!
Lola: Hey it wasn’t my fault. Adam is a pre-existing condition.
Lola: Hey it wasn’t my fault. Adam is a pre-existing condition.
by builtforspeed July 25, 2018