The Romans gave us Venus and Cupid. The Egyptians had Bast, the cat goddess. The Greeks - Aphrodite and Eros. The Moroccans had Qandisa, who made men go insane.
Given that royal marriages were based on politics rather than love, concubines were very common. That doesn't sound right as the women were not thought of as immoral or loose women and were often accepted by society. There is not much evidence of wives having concubines (or concubinus - Roman for a male version) but I'm pretty sure they did. They do in my books anyway. The peoples of the Dark Ages had, I believe, a good chance of finding love in all its forms. Marriage was the official public declaration of status. It could work and I'm sure many did. Where it did not offer a true relationship of the heart, people would look elsewhere. To have gods such as Freya, Ing and Frigg who portrayed love in an earthy way unlike the soppy ways of Valentine says it all.
Incidentally the word 'love' comes from the Anglo-Saxon word 'lufian', which means "to love, cherish, show love to; delight in, approve".