He openly flirted with F'lhaminn, Moenbryda, Yugiri (indirectly, he wanted Urianger to check her out for him when they chatted via linkshell in one of the main scenario quests). Heck, even at the feast, he was off somewhere else, flirting it up with some random miqo'te. That he does this in front of Minfilia is a pretty clear indication that he has no interest in her romantically.