I'm sure that if he did cheat she's aware. Maybe they have a thing that they don't wanna say because people who aren't open minded would take it the wrong way. Like, maybe there's a "lay where you want but bring your heart home to me" thing.
I don't think announcing something like that would be a good idea given their fan bases.
The trend I'd like to see discontinued is people assuming they know everything by seeing a picture that could actually mean 1,000 things. Why create stories and peddle them around as fact when they can't be proven by anyone other than Zayn, any girls involved, and the LORD?