Responses

From reading previous comments and novel spoilers , if I remember correctly, he doesn't love her in that way. It's more of an obsession/understanding they share between each other. They rely on each other in a really twisted sense and he wants to be there for her but also wats to be the o n l y one there. so nah no incesting from the novel standpoint
if fountain or whatever thinks incesting Roxana is okay and that not even that long ago it was legal does that mean Dion also wants to incest her
p.s i know incest isn't a verb but in the future it might become a verb new words and verbs are always getting made up.