I've just finished series 2 of The Good Wife, and I wondered why everyone believes Blake when he says that Kalinda and Peter had sex when she was working for him. He has no proof, just a load of guesswork. He's lied about things in the past, and nobody who knows him really trusts him. Alicia knows that Blake tried to implicate Kalinda in an assault by leaving a glass with her fingerprints at the scene of the crime. So why is it that when she hears about the sex allegation, knowing that it originated with Blake, she immediately believes it to be true?