wow, i never saw this thread!
i'm single, so of course i'd go for it. apart from that, my answer would be, it depends on my partner. if i truly love him, and he loves me too, i wouldn't leave him for anyone in the world. not even be tempted. true love is too hard to find to throw it away that easily.
...
ok, wait, let me rephrase that - it would be enough if i loved my partner, and thought he loved me too. i wouldn't have left my ex for mika. but my ex left me, so let's face it, i'd be totally screwed if i had gotten the chance but said no to mika because of such a guy!