On Faithfulness (Odyssey)

In the tumultuous years of modern life, we have always wanted someone who could stand by and for us. Someone who would respect and view us as partners and not just mere servants or the like. Most of us, if not all of us, look for that someone who would be true and faithful to us. But how do we define faithfulness? Is it the ability to resist any form of temptation? Or, it is the ability to bear in mind the existence of our significant other? Does the definition of the word change through time?

Odysseus is loyal as he puts it. He came to live with Circe and Kalypso. He had enjoyed his years of stay with these two women. Now, isn't loyalty and faithfulness tied with one another? If they are, can we then consider Odysseus to be faithful still to Penelope? If they are not, then what is the difference between loyalty and faithfulness?