The detail from CH that JA spoke of calling an atty during the May 26 texts is totally interesting. I guess I ultimately don't believe she brought up the sex tape. I don't because if she had done so I just cannot imagine he would let her take naked photos of himself, even with his own camera. Way too raw a topic, no matter what she could have said to him.
I think her explicitly denying the tire slashing and journal theft, in writing, just after the texts, suggests that his threat to make those things public scared her and she was threatening him with legal action for libel/slander if he followed through.
I think the Hughes' couldn't find the one great big thing that set him off on May 26 because there wasn't any one single one. She could have done that one more stalking thing that totally tipped the scale for him, that made his blinders fall off, and the tide of realizations of all she had done to him hit him all at once.