Put me in the screenshot if this manga is responsible for introducing no fault divorces in Japan. I can't even imagine the shenanigans or outright criminal shit people resort to when they have no legal recourse.
So, I got worried a second when Rei and Rio regained their cool and simply denied because it's true that Mahoro does not have undeniable proof, only circumstantial pieces. She had both clear cut evidence, the used condom with both DNA and a photo op with both getting out of a love hotel and she squandered both.
Then again, the fingerprints and the Twitter account might enough. Still, I think Itsuki might save the day and add what he might have found from his side. Rio is so smug I don't think she went to great lengths to hide anything, with the reasoning being if Itsuki was there more often and a better husband, he would know how much he's neglecting his 'superior' wife. And if he didn't, it would only prove her right, in her deluded mind.
He has money, so I'm sure unlike our dorky Mahoro, he just hired a professional and got all he needed.
Now he's mostly here for the tea 😈