Aidan was hesitant about any woman Fin brought around, not that there were many. It was much easier to assume it wasn't going to be permanent or even somewhere in the "long-term" range. But he was still polite, nonetheless.
After greeting Fin, Aidan shook Cho's hand with a large, albeit fake, smile. "Nice to meet you, as well." It was much too soon to assume anything about their relationship, but that didn't mean he couldn't embarrass Fin. "Did Fin tell you anything about his 'problem' yet?" Aidan, of course, was not referring to Fin's ex-wife or the divorce.