Shortly after my now-fiance and I started dating, he had to go on a month-long business trip to Australia. Our relationship really deepened while he was there (we first said "I love you" over the phone), and we missed each other like crazy. So I picked up one of those "football e-savers" from DFW-LAX the weekend he was flying home, and went out to meet him. Only problem is, he had a first-class ticket back to DFW, and I was in coach (a lowly GLD at the time, and my upgrade didn't clear).
Having down SYD-LAX myself in coach (twice), I told him to go ahead and take the first-class seat, he deserved it. But he was like, "No way," and we sat together allllllllllllllllllllllll the way at the back of the two-side of an MD80. Good thing too... if he'd taken the FC seat, I'm not sure we'd be getting married right now
It's not so much chivalry, as just wanting to sit together. We both travel enough as it is, and spend so much time apart... when we get to travel together, I want to
travel together!