Under normal circumstances, I'd say that I would neither flirt nor otherwise go after a friend's ex because, up until meeting Blue, I'd met no one worth losing a night's sleep over, let alone a friendship.
But...and please bear in mind here that I'm not lucky enough to have
any femme friends who live this side of the Atlantic, let alone locally...say I'd met Blue and he
was the ex of an (imaginary) best femme friend of mine. Would I flirt with Hym in front of said (imaginary) best femme friend? No, no need to rub salt in the wound. But would I otherwise go after Hym? Absolutely. I'd probably feel shit about it, but selfish as it may seem, knowing what I do about Blue, there is nothing on earth that would stop me from trying to be with Hym.
Which makes me, I guess, judging by most of the responses here, a potentially crappy friend. Sorry
Words