All's Well That Ends Well
If an antagonist is a character that gets in the way of the protagonist, then Bertram is definitely our guy. After all, his unwillingness to have sex with Helen is the only thing left standing in the way of our girl's happiness after the king of France grants her the right to choose any husband she wants. This may not be fair to Bertram, but remember, this is a Shakespearean comedy so somebody's going to get married and live happily ever after, whether they want to or not. Go to "Genre" for more about this...