He could understand and sympathise with Simon. Not that he was in love with Cami, but he knew how he'd react if Dean hurt her. Difference was, Spike wasn't human so he knew he could get a few licks in. Whether he'd get any more than that, however was hard to say.

"Yeah, I got that. He touches her again, I'll break his sodding neck for you." Well, that wasn't meant to slip out... But he just moved right on along anyway, oblivious. "She doin' okay?"