I think that Mary sucks here. Normally, I would empathize with her. However, using financial advantages as leverage and bribing, guilt tripping, and even terrorizing her children is toxic and manipulative. She basically tells her children that choosing to stay with dad is equivalent to destitution and despair. She seems completely okay with the idea of them choosing her for money rather than affection. This shows that she cares more about winning than love and relationships. If she cares for her children as much as she says she does, she would have paid for her son and daughter’s expenses and provided better educational opportunities no matter who has custody.