I am a Cotto fan, and I was just watching an interview where he said he was the one that stopped the fight. I have not seen this video here on this site so here it is. For those who don't speak spanish a quick sinopsis of what he says is that he took the knee in order to be able to fight another day, that his health and his family are more important than looking his 0. He felt that he was wining the first part of the fight but started to feel the punches on the second part of the fight.
http://www.miguelcotto.com/smf/index.php?topic=11425.0