Disclaimer: House is not mine.
Wilson knew.
Cuddy had hedged on House discovering their relationship (the word still seemed so foreign in her mouth, even after several weeks of awkward moments strung into a series of dates) before anyone else. He might profess not to care about other people, but that didn't mean he didn't pay attention. But House had given no indication that he even suspected a change in the behavior between Cuddy and Cameron.
Wilson hadn't either, but it was different. Cuddy knew he knew, even if he hadn't said anything yet.
And Cuddy was dreading the moment Wilson would confront her. She had run through the conversation a dozen times in her head. Each time was slightly different, but not a single one resulting in a happy outcome; Cuddy imagined that he would lecture her for her stupidity--getting involved with an employee, and not just for a clumsy one-night stand with a pretty boy like Chase, hell, not even House--or express his concern for Cameron's impaired judgment.
So when she passed Wilson in a deserted hallway in the hospital late at night, her heart was beating so hard that it felt like it was in her jugular. But he gave her nothing more than a searching look and a cryptic "good luck" and suddenly Cuddy knew:
Wilson loved Cameron too.
Fin.