Responses
No, in a previous chapter, Ines and her brother talk about how Oscar plans on taking Ines as a mistress because she wouldn't be allowed to marry again after Carcel dies. So Oscar would still need to get married, and that's why he's fine with marrying Delores. He believes that she would never dare to stand in his way and prevent him from taking Ines as his mistress.

So why would Oscar get married if he wishes to have Ines and while he was speaking to duke escalante he seemed quite sure of himself that death will follow Carcel in war wouldn't the marriage hinder his plan to have Ines ? Caus i don't see any benefits from the marriage. Also if they know that Miguel is su*c*dal why not choose to keep him a bachelor?