There are girls working on tens of sites in the same time. xlove is not owned by MFC, they have a different contract and separated payment. Yes, they know girls are in other places too, they don't require exclusivity ( they wouldnt have so many girls if they would) . On xlove the models receive 45%-50% like on MFC, but only a few of them are on there because it's a french site, so BRB on MFC means private on another website, but not necessary on xlove
I wouldn't advice any model to work on a single website.