Ed laughed when she said that. Maybe he should be offended, but at this point it was just funny when she made that statement, especially since he'd kind of figured it out already and he didn't really need the reminder.
"You don't have to have sex with me to sleep with me, you know," he teased. Not that he would object to sex. He was a 20 year-old male. He definitely wouldn't be turning it down if she wanted to. But it should be pretty obvious that he wasn't just trying to get in the girl's pants.