User blog comment:Sachoras/Cersei - friend or foe?/@comment-5014364-20121221033022/@comment-1469568-20121222170238

Tywin is concerned purely with maintaining and asserting the supremacy of his House, and will do almost anything to achieve this, including the murder of children. He's about as villainous as it gets.

And what relationship? he makes her his cupbearer becasue he finds her entertaining. Ho do you think he would have treated her had he known who she really was?