Isabella didn't want revenge on Cathy. They were like sisters. Here she is, a single, marriageable woman stuck out there around the Yorkshire Moors. Her closest neighbor & prospect is Henley, Cathy's brother. That's why church, church socials and small parties were so important to meet and mix. Now here comes Heathcliff
Olivier!single and a good financial prospect, especially since he just bought Wuthering Heights, relieving Isabella of Henley. But HER brotherLinton protesting such an interest, after all he still saw Heathcliff as below them, regardless of his money; and then Cathy's seeming petty jealousy just motivated Isabella to marry Heathcliff more. BUT Cathy KNEW Isabella was not the stuff of what Heathcliff was madeCathy knew because she & H. we're of the same cloth. And she KNEW that H. marrying Isabella was just a way to get back at her. When you are like a soulmate with someone, like they were, you KNOW their mind.
Isabella, I believe, did love H. but didn't get him at all, not really, eventually realized he really still loved Cathy, and her life at W.H. really became that drudgy thing.

I got the impression she loved him and the money and wanted some revenge on Cathy

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I believe that she does love him, but I also
think there is a bit of spite toward Cathy.