I hope DPC will show a little subtlety here.If only the MGs didn't suddenly become close friends with each other, but here we are. The MGs vs SGs divide can't become more apparent now folks.
Bianca (and other things the MC does during the Panty Party and Halloween), so far it's clearly the MC taking the road of an unfaithful guy. So when he gets caught with his hand in the cookie jar, if he gets smashed by the group of friends, that's normal.
(Note, however, that DPC prevents us from having an MC who's a huge hypocrite and a total asshole, because you can't tell Rusty that infidelity is wrong and go on about it with Biancha, and you can't say “I love you” to Sage (and M/J too, I think) if you have too many cheat points).
Zoey, it's not the same at all. She's the girl he was in love with, who walked out of his life for a few months and comes back. It doesn't deserve the same treatment by mutual friends as an unfaithful MC.