Can a resident partner overstay the 90 day rule in Spain?

Question

If you become resident and your partner has lived with you for over 15 years, is she allowed to stay in Spain over the 90 day rule?

Answers

These are the answers of some Facebook group members:

“No, she has to apply for residency just you you.”

“If you and your partner have lived together IN SPAIN for 15 years she’d be allowed to apply for citizenship after 2.5years.”

“Only if she applies for residency as well.”