He hates her because HE wants to marry Maribel so he's bitter, angry and sad that he can't marry the love of his life for obvious reasons, yes he only married her because he was tired of his mom constantly introducing females to him, while also doing it so if the Familia suspected the relationship between Maribel and him he can use her, and like I've said he's hateful because imagine marrying a person you don't love and not being able to marry the person you love.