I thought of something else @The_J -
If her current fake husband has already threatened to report her after a regular fight, how do you think he's going to react when she leaves him and instantly fake-marries her ex-boyfriend? He will ruin you.
Her current one is as real as it gets (in the way that they're regularly...er....intercoursing; which we could do too, for the sake of this thing).
But yes, this is an added problem.
(unless I marry her in France, different authorities then, and he'd not need to know, but hell, this is complicated

I hope that this possible oversight in the visa regulations might fix the issue, would make everyone's life a lot easier.