Emilia is a very strong willed woman, and while she was willing to get involved with her husband's machinations to a point in order to please him, when she saw the completely terrible things he had done, she was willing to call him out on it publicly, even when he was threatening to kill her. Emilia is cynical and worldly and is distrustful at best of her husband.
On the other hand, Desdemona is so in love with her husband, she's willing to take whatever he dishes out to her, no matter how much it hurts or humiliates her. She loves him to the point of complete blindness that it is often inferred that she doesn't struggle too much when he kills her. If you want to see a truly heart breaking rendition of this, rent the 1995 movie version of Othello.
Bianca is a courtesan, which is sort of similiar to a prostitute so she sees most men accordingly, though she has a soft spot for Cassio. She allows Cassio to repeatedly tease her with the promise of marriage, though she should know better.