The better answer would have been "That's a large responsibility; let me think it over."
But nope, can't have commitment in a harem series.
Yoake you limp-dick bastard you could have had the world in your hand.
Any sane man would be already on their honeymoon with elf wife. But the show must go on I guess.
Specifically, becoming the legal husbando of the elf queen, which would have made Yoake a Prince-Consort (at least) and married into a very wealthy family, rather than bumbling through high school missing homework because of magical neurological impulses.
Or, phrased differently, he could have been happily married to a Christmas Cake Elf Auntie Sugar-Mommy who wanted to become that rarest of manga things, a happily married MILF-elf with a happy family.
Yoake is fine going to third base fondling her nieces, but isn't interested in babymaking Snu-Snu with a Christmas Cake elf of full legal majority? Babymaking. Snu-Snu. Elf. Wife.