I mean, yes, Cecil is over-possessive and creepy and disrespectful of other's free will. I thought that was well established from day one.
His dry wit and generally good intentions generally tend to balance out those aspects of his character and make him overall likable, but he's the sort of character who makes you cringe occasionally. This serves as an excellent foil for bright-eyed, madcap, foolish, good-natured Bertia, but whether it would all be okay in a real-world relationship is a much more complicated question.
But I respect those who think his actions here are not-okay, even if I'm fine with them (considering the totality of the circumstances) myself.