The "Family member of an EU citizen" card is a type of residency permit that allows your non-EU spouse to reside in the EU with you. It's basically one of the paths you can use to seek residency for her.

You basically have to arrive in the EU, register under the same address (in Spain they call it the "empadronamiento"), and then to support her application you would need to get private medical insurance for her and show that you can financially support her as well.

The good thing is that from the moment you apply for residency this way ("Family member of an EU citizen") she is legally allowed to stay for the duration of the application process as the ball is now in their hands. Once approved the 5-year card will be valid from the date you applied, not the date of approval or card issuance.

Now this is useful if you intend to live/stay in the EU for longer amounts of time as otherwise - on a purely tourist basis - she would have to abide by the same rules as all short-term visitors. Some have tried to bend this by travelling together and quoting that your spouse is always allowed to travel and stay with you for however long you like, but the stark reality is that without a residency permit for her you are going to encounter trouble with anything that exceeds the basic tourist limits ("rolling window" 90 days out of 180).

Thanks. I understand what you are saying. But I do not accept why my wife will and should encounter trouble. You like the border guards are linking unrestricted multiple short stay EU movements by a UK citizen when accompanied by their EU spouse to be only possible with a resident card. This is clearly against EU rules and EU rules trump National practice in the end.

Will have to escalate with Portuguese Immigration authorities…..

Appreciate evidence of actual Border Control practice from members.

All I'm saying is that how things work in practice is generally more important than the small print that might well be ignored.

For instance you can go for up to 90 days, but if you stay longer then depending on the country you might fall foul of the requirement to register within that time. So there's these mini-pitfalls to look out for.

Also, without residency I assume she would need to go through the machines each time just like a tourist, and those will be registering all movement in and out. Before that nobody really checked the stamps, at least when it came to UK citizens in Spain.

Definitely carry a marriage certificate with you just in case. If I was in a similar situation I would be tempted to seek residency in whichever EU country is the most lax for UK nationals. With a card from there travel will be easier across the EU (especially if your wife were to fly alone). Just saying...