He catches her eye, a faux-unamused expression on his face.

'I'm goin' to assume you're takin' the piss, an' that's not a real thing where you come from.'

But you never know.

'An' what I meant is if I'm with a bird that makes me not interested in other birds, then I wouldn't cheat.'

...even before he's finished, he's thinking that doesn't sound much better.