This wasn't an outcome he predicted. He figured they had been on the same level, similar thought process. Apparently not, because you're upset, and he's staring at you with a raised eyebrow.

It was just about the sex. That's merely all he wanted out of this interaction and he thought you had knew. But God forbid anything goes his way, because you obviously wanted something more. 

The mutant turtle shifts his stance and glances away. “Will a sum make it better?” He asked nonchalantly, arms crossed. Maybe you'd accept money as some kind of compensation. It usually cheers people up.