I remember she said it in the game, and wiki stated it as well.
In anycase that wasnt what i was talking about. she being dark side or light side, sith or jedi wont matter, they were not a kind of people to lead their lives by lust or rather to be more correct, those kind of instints. They were not Nihilius wich was an extreme case of complete deteach of reason, dare say conscious.
Either Revan or Bastilla were driven by their convictions, they lead their lifes with conscious, as a jedi or sith.
It's not like he must kill Dooku right after turned Anakin, like Tenebrous, he could keep 2 apprentices together. And Dooku, according to EP III novel, was going to corrupt Anakin for Palpatine after the duel, of course Palpatine betrayed him.
Yeah there can only be two. Palpatine meant to get rid of dooku as he did with Maul or tried anyway if a new more powerfull potencial aprentice were avaible to him.
Off couse i belive once the jedi were no more the rule of two wouldnt be as much important.