Your feelings are valid. ignore the trolling and goading about "sucking it up"
As long as you pay she will continue to behave the way she does. Stop paying. Stop working. The kid should be at school. Who bought her a computer or mobile phone. Shes spoilt. You consult a lawer. Try to get her visa revoked suggest couple counselling- if she refuses thats grounds for legal action.
Spending so much time on social media is a terrible example for the child.
You need her out of your life and out of your country.
She sounds like a parasite to me and she is exploiting you using the kid.