Le Morte D'Arthur
How we cite our quotes:
And so whan they were abed bothe, Sir Trystrames remembirde hym of his olde lady, La Beale Isode, and than he toke suche a thoughte suddeynly that he was all dysmayde; and other chere made he none but with clyppynge and kyssynge. As for fleyshely lustes, Sir Trystrames had never ado with hir. (271.45-49)
Although Trystram marries Isode le Blaunche Maynes, he never sleeps with her, which just might sting the blow of his betrayal of his other lover, la Beall Isode. In fact, in a way, it puts the two on an equal playing field of sorts, considering the fact they're now both married, and still head over heels for each other.
"Sir," seyde Sir Trystram, "Now I undirstonde ye wolde have my succour, and reson wolde that I sholde do all that lyyth in me to do, savynge my worshyp and my lyff, howbehit that I am sore brused and hurte; and sytthyn Sir Elyas proferyth so largely, I shall fyght with hym." (376.23-25)
Trystram demonstrates his loyalty to Mark as a vassal, despite the fact that he is sleeping with Mark's wife and that Mark has been a real jerk in the past. Trystram's refusal to let his relationship with Isode get in the way of his fulfillment of his obligations as vassal and nephew to Mark marks him as a "true" knight, which the highest praise Le Morte can give. Chivalry, it seems, is far more important than being a nice guy, which is why Mark can step all over Trystram one moment, and then totally count on him the next.
"My lord," seyde Sir Launcelot, "wytte you will Y ought of ryght ever to be in youre quarell and in my ladyes the Quenys quarell to do batayle; for ye ar the man that gaff me the hygh order of knyghthode. And that day my lady, youre Quene, ded me worshyp." (597.17-20)
Launcelot explains the origin of his loyalty to Arthur and Gwenyvere. When it comes to Gwenyvere, however, he doesn't exactly tell it like it is. He claims that his loyalty to her started when she showed him great kindness at his knighting. But Launcelot, we know better. You're loyal to her because you love her.