He doesn't want the political responsibilities that come with marrying a Princess.
Why do I keep re-reading the Supper Smash Bros Mishonh from God fanfiction series even though I know it is god-awful, racist, homophobic, filled with spelling errors, butchers everything that is closely related to Smash, and would be a LOT more offensive if it wasn't so horribly written? (For further reference, it is VERY hard, to the point of being impossible, to offend me, and even I find this fanfiction (which is thankfully a troll fic) offensive)