Evelyn Pomeray and Willamine "Billie" Dabney
Kerouac does most of the work in this comparison. Check it out: "There's not much difference between [Billie] and Evelyn when you listen to their talk about Cody except in Evelyn's case I'm always fascinatedly interested – Billie actually bores me tho of course I cant tell her that – Evelyn is still the champ." There you have it; both women are crazy about Cody, but there's a reason Evelyn is married to him and Billie isn't. There's also a reason Jack is fascinated by the thought of "getting" Evelyn in some sort of eternal, karmic sense, yet doesn't want to even think about committing to Billie in this lifetime.