The opposite of a "power couple." Flaccid Couples are weakened by their relationship status, and continuously becomes worse at activities they used to excel at. Their relationships drains them of their skills, leaving them flaccid and powerless.
Bro 1: Old Jen used to be great at fantasy football, but she's really tanking this year.
Bro 2: Well she's been dating Josh for a while now, they must be a Flaccid Couple.
Both Bros: (weep for their friends)