To be fair, Adrian wasn't trying to get Gray into any trouble. He just couldn't help being amused at the irony of it all. He knew Ali's friends weren't exactly approving with their relationship, so it amused him to know Katie had slept with Gray, even if she was being completely thick about it.
This was an ingenious plan, he thought. Ali would stay here, Gray would get some time alone with the blonde. It was perfect. He was immensely pleased with himself for coming up with it.
Maybe it was an asshole thing to do, but in his defense, he needed this time with Alicia just as much as she did with him.