For a man that makes $60+ million/year and is worth nearly half a billion, paying her $87k/month is a drop in the bucket. The problem is this............why does she need $87k/month. She was making $9/hr working at Gucci? He could pay her $20k/month and that's still a big come up. She is helping raise his kids so I can definitely understand wanting to take care of her.
Is she gonna stick around for the long haul? Maybe. My hunch is that (if she's smart), she socking the money away and then might split when she's tired of him. Of course she could also be "the one" and they live happily ever after. Still, rich dudes need to either stay single or marry up. If you're making millions like that, marry a doctor or physicist or something. Combine your athletic ability with her smarts to make some super kids. Just marrying a sexy woman.....shortsighted. There's a good chance he's covered himself legally based on the way he handled the surrogate/kid situation...so there's that.