was first applied to anyone boring, socially awkward or uncool.
They were just a little bit "off", fair game for exclusion and mockery.
There are plenty of things that both of you will love.
Movies and shows like Star Wars, Game of Thrones and Hunger Games will satisfy both nerdy and non-nerdy tastes. Even if your tastes in literature don't greatly overlap, he will love to hear your thoughts on your current novel.
But physically drag him away from Github and he'll soon forget about debugging his code, and prove to you that nerds really do make the best lovers.