I don't really think I can answer either way without more detail. Why do you dislike her? Does the couple know this? Is it simply not getting along or has she done something horrible? Etc.
If you just generally don't like her then I think it's very rude. If there's a specific reason as to why you don't like her, eg, she is hateful and nasty to you guys, tried to break you up, etc then I think it's more acceptable.
In previous relationships my partner was friends with people I didn't like or didn't like me and I'd have been fine to not be invited because we had made no secret of our dislike of each other... Though still weren't nasty. Neither of us wanted to be around the other so I was happy to receive no invite to events. It was expected.