but there's always a point where you can exercise free wil
I could question your logic on this all night.
By default, if you can't think clearly? It impairs decisive ability.
If you can't decide well? You're not deciding freely (as in taking all known factors into account and with full knowledge of what you're agreeing to.)
By the way, what's your guarantee YOU are the one deciding freely? Especially since you're so stuck up in comparisons to someone so close wrapped in the situation that is in HIS interest if you hate her.
Looks to me you're rather busy looking for someone else to blame for the whole mess, instead of cleaning the mess up and getting out of it, before it spirals even worse than it is already.