Lots of guys say/have said this exact line. It's partly to big themselves up a bit and partly true.
A guy wont usually need to find a girl that attractive to be open to having sex with her a few times.
It's just 'guy talk'. There are many worse things you could have heard him say.
And to the people stating that "it's all he wants from you"
No it isn't. It means he's not really going to go out of his way to have sex with her (he probably doesn't find her that attractive), but if the option came about - he'd still do it.
Its not likely he fancies her.