No,I am not trying to link these games.

(SPOILER)
I think you're forgetting that the Sanctum 'ok'ed the Purge, y'know the murdering of thousands of people just because they lived next to a fal'Cie because any one of them could have been a l'Cie. Letting in a Pulse citizen who could potentially be a l'Cie with a Focus to destroy Cocoon wouldn't make much sense.
I am talking about FalīCie, not humans.
Humans are afraid of Pulse beings and think they are corrupt.
But FalīCie know they arenīt corrupt but are only enemies.
But Cocoonīs citizens came from Pulse in the first place.
So what would prevent a FalīCie to enslave a human that try to enter from the outside?
Specially ones that want to live there.
I donīt get it.

Vanille remembered. If Fang had a husband it would have been mentioned when the whole truth came out. Assuming that's it's a sore subject is incredibly strange considering that a husband was never mentioned. As far as I've seen the only time Fang shows any inclination towards a sore subject is when she was talking about Vanille.
It is not everyday one likes to talk about a husband who did something you didnīt like.Specially one that abandoned you.