NGL if the guy gets married in the end, I actually hope it's with the composer so they could just do their own interests (magic tools and making music) without having to deal with the societal pressure for marriage or kids.
This manga is well written so far. So if they do have him find a relationship, that is likely how it will go.
Also in real life when people who aren't typically interested in relationships or marriage do find partners, it is usually like the one you just described. So it's the most realistic outcome for this manga.