lack of sex flu
A fever, upset stomach, sore throat, broken big toe, basically any ailment or sickness can be tied back to a lack of sexual intercourse.
Sally: "man I think I'm getting sick"
Bob (husband that hasn't had sex in a while) : "sounds like you got the lack of sex flu, it's been going around" .
Bob (husband that hasn't had sex in a while) : "sounds like you got the lack of sex flu, it's been going around" .