Archived link: http://archive.is/Dw4IM

Guy confronts his GF who cheated on him, and ends up taking her back.

The manipulation is palpable.

What stuck with me the most was the guy she cheated on him with. In the original post, it was the other guy who tipped off OP when he learned she was in a relationship. When OP confronts her, in a "show of faith" she calls up the other guy to prover her loyalty

She even called the guy up and confessed and told him she had to stop right in front of me. He simply told her that she was cold and that I shouldn't take her back. She hung up on him.

In my experience, I've only seen girls described as cold when they've displayed a shocking lack of empathy and concern for the welfare of others, to the point that it surprises bystanders.

EDIT: As others have pointed out OP made an update that after hearing readers' feedback he is now leaving her.