CFV:
He's definitely got a belly forming and I enjoy when he wears shirts that'll show the progression.
You say he's not your type, but are you sure?
You seem to be paying a fair bit of attention to his body. Not saying you should be a homewrecker though; that's bad.
Is his girlfriend/wife an FFA as well, or perhaps a BBW?
It's a pretty well known fact that being in an LTR with a fat woman is likely to be a fattening experience, unless he's already fat. So if she's fat, there's a good chance he'll continue to expand and get even fatter.
