Awww… that’s a bummer! Urban Games posted the preorder options in July to their website where it was made clear that both retail and digital editions will come with the Steam requirement: http://www.train-fever.com/2014/07/train-fever-now-available-for-pre-order/
But hey… you essentially talk about sharing your copy with your partner. You can do that with Steam too. I admit, it’s not as easy as installing a DRM-free version on two computers but since you have bought the Steam edition anyway, you might want to give it a go:
What exactly would you like to do?
- Play Train Fever on two different computers or
- Play Train Fever on two different computers simultaneously
The first one should be possible through Steam’s family sharing. It basically allows you to share your library with other devices and accounts: http://store.steampowered.com/promotion/familysharing
The second one might be possible as well but brings us into murky territory. Not sure how Steam’s EULA is on that (and Urban Games’ policy on talking about it on their forum). It relates to Steam’s offline mode.
*edit* made links clickable