I doubt this was a surprise to Huma. She and Hillary! probably no doubt know about his sexting, they likely approve of it (such is their deviancy). In fact, it would not surprise me if this was a Clinton-engineered wag-the-dog.
A few days ago:
"Anthony? OK. Here's what Hillary wants you to do: In your next sexting, pose this way..."
"Then later, I'll announce I'm separating from you. No, no! It's just for the press, to take the heat off of the campaign."