It does seem there is definitely something, something very bad that he found out but I can't see it being that because, like JA's stupid story about him being one....who'd be intimate with someone they thought was a pedophile? I can see overlooking a lot of things about a person and still having sex with them, but not that, which is why her story is so ridiculous.
What woman (or man) would not only continue having sex with someone they thought was a pedophile, but even encourage it by playing along with the spiderman underwear and schoolgirl outfit. Her biggest mistake in this trial IMO. At least the most glaring lie of so many.
I think the bad thing... was actually a lot of bad things... all the crazy things you've done ie... hacking,spying,slashing tires,tailing him on dates, the email to Lisa, etc etc...He had previously kept that stuff from CH,SH and LU ...and she knew it.