Upvote:2
When traveling to Spain together [with a Spanish national] does the 90/180 day Schengen rule apply to me?
When travelling with (or joining) an EU citizen the 90/180 day Schengen rule does not apply to you.
Since you, as a US citizen, do not require a visa to enter the Schengen Area, you do not require a Visa for family members of a citizen of the Union.
do I need to apply for anything to allow the longer stays?
For a stay longer than 3 months in Spain, you must must apply for a residence card of a family member of a citizen of the European Union.
This must be done within three months of your date of entry into Spain, at the Non-nationals Office. You will be will immediately be given a certificate of application for the residence card.
Note: I could find no exact information what a spanish citizen, returning to Spain for longer than 3 months, must do. I assume residence registration at the relevant local police station.
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