I agree that we'd probably see something similar to the relationship that Bellamy has with Kane
but somehow, there's still some distance between them there (among other reasons, Kane being part of the council that floated Aurora) ... whereas from his relationship with Octavia, we know how much he values family so I'd imagine that he'd be super close to his dad and would be protective over him too, though in a different manner.
There was no concept of marriage on the Ark, so I suppose that a lot of the Arkers might not have been exclusive.