Abu Qilabah narrated from Anas bin Malik, :
He (Abu Qilabah) said: If I wish, I could say: 'The Messenger of Allah said' but he said: The Sunnah when a man married a virgin after he already has a wife, is that he stays with her seven (nights). And when he married a matron when he already has a wife, he stays with her three (nights).