Not the Boys
The problem was that Mark didn’t have this proof because he wasn’t planning on meeting the boys. Instead, he was using it as an excuse to free himself from Kelly. However, Kelly never asked to see any proof, which was a relief.
Not Going Anywhere
Kelly was behaving completely out of character. She didn’t seem to care much about what Mark was planning. However, this was because Kelly had her own plan that she hadn’t shared with her husband. She had been planning this all along and wasn’t going anywhere.