Coming from Spain, the relationship was much more complicated than one of simple negation. For example, both Muslims and Christians believed in the virginity of Mary, and the miracle of immaculate conception. This was in stark contrast to the Jewish populations, which would show in their interactions with each other, and the Jews.

There is also a distinction between what we might refer to as the political perspectives of the Crown and the everyday life of the peasant. The former had serious issues with which to contend. For example, Alfonso X had to show his piety and faith towards the Christian Crown while he was attempting to win the title of Holy Roman Emperor. The latter, however, had to deal with the realities of a rapidly expanding empire. Under Fernando III, Spain's territories nearly doubled in a period of less than 20 years. There were not nearly enough Christian subjects to successfully colonize the new Muslim territories. Thus, we can imagine that groups of Christians and Muslims interacted with reasonable levels of cooperation that is not recorded in something like the Cantigas de Santa María. It is extraordinarily difficult to conceptualize what these interactions were like, owing to lack of sources about the "common person", but we are reasonably sure about the groups of populations that existed and where they lived.

It's also worthwhile to note that exchange of ideas, both religious and secular occurred throughout the Iberian Peninsula and greater Europe. A large number of scientific, philosophical, and theoretical treatises were exchanged throughout the Muslim and European territories. It would not be a far-fetched statement to say that we owe a large part of the Renaissance to the careful record keeping of the Muslim rulers. As a result, Christianity knew they had a special sort-of relationship with Islam that could not be terminated completely. Of course, this also worked the other way--one of the main attacks on science in the Middle Ages was its place as a "Muslim field of study", rather than one sanctioned by God.

Further Reading: Remensnyder, Amy La Conquistadora: The Virgin Mary at War and Peace in the Old and New Worlds (Oxford: Oxford University Press, 2014). Nirenberg, David Communities of Violence: Persecution of Minorities in the Middle Ages (Princeton: Princeton University Press, 1998) Catlos, Brian A. The Victors and the Vanquished: Christians and Muslims of Catalonia and Aragorn, 1050-1300 (Cambridge: Cambridge University Press, 2004.