Golden_eve, I think there's something else to consider: your abuser groomed you to want their approval. At some point early on in the relationship, they did give you validation and love, probably a lot, and you stay in the relationship despite the abuse because you think that if you just act the right way and give them what they want, they will be their old, nice selves. They withhold love and validation to get what they want from you, and it is, indeed, abusive. They groom you so that you have to get your validation from them so they can manipulate and control you.

And yes, it's hard to unlearn. And your subject line is spot on: we don't need to base our value and self-worth on the opinions of others.