Kindness isn't something that is valued in the First Order, but Mitaka has always been nice to Finn even though he's an officer and Finn is just a Stormtrooper.

Finn likes him, appreciates being treated like he's more than a number. He thinks maybe Mitaka is every bit as conflicted and confused as he is, but there's no way of finding out. They aren't friends.

But that doesn't stop them from being intimate, maybe just once, maybe several times but always in secret.

Bonus if they're both virgins and if Mitaka approaches the relationship with a degree of seriousness that surprises Finn.