I always thought this was what was going on in the Miller's son:
"Ooh, what if I marry the Miller's son, he's so attractive... but ugh, then he'll get old and cranky and fat, gross. Well, what if I marry a rich businessman instead? But ugh, I'll have to take care of the babies and get old, gross. Well, what if I marry the Prince of Wales, he's the most eligible bachelor around... ugh, then sex will end up just being a duty. So basically, whoever I marry, no matter how high born, it's going to stop being as fun and sexy as it is now. So I might as well just stick with the Miller's Son, he's as good as any, and I'll enjoy the moment!"
She's realizing that in the long run, the Miller's Son is no better or worse than anyone else, so she makes up her mind to marry him afterall.
In my pants, she has burst like the music of angels, the light of the sun! --Marius Pantsmercy