Recognised medical condition arising from a period of prolonged
cohabitation with a recently
exed spouse or domestic partner, whereby hitherto amicable separations risk
lurching into loathing and recriminations due to sudden lack of shared interests and/or future aspirations, see also ex stress.
Why's Dave being such a
douche at work?
Oh, he was diagnosed with amicable fatigue - give him
ten days and then go for a beer with him.