Gracias, Marta!

But if you have this card "Tarjeta de residencia permanente de familiar de ciudadano de la Unión", are you considered under regimen comunitario? Will it be better if you are under regimen general?

The way I understand it regimen comunitario means you are in Spain because of your ties with an EU national. And with regimen general, you are a legal resident by virtue of continuous stay in Spain. Is this correct? I hope I am making sense.