One of my coworkers (let's call him Paul to avoid confusing pronouns) asked me if it would be wrong for him to hook up with his uncle's ex-wife (just sex, no relationship). He asked another coworker (let's call him Bill), who said that she's still family, despite her being divorced from Paul's uncle for like a decade. Apparently, Paul was never close to her, so no awkward aunt-nephew dynamics going on.
My thought was basically, like "Dude. She had sex with your uncle. Gross. No."
Would it be "wrong" for Paul to sleep with his uncle's ex-wife? Why/why not?
Like I said. You don't share partners with family. You just don't.
ETA: He's wondering if it'd be "wrong". I'm wondering if anybody else is like "uh, no." to this. Would you do it, given the circumstances?