Can my ex-wife be estopped from denying an existing agreement?

Can my ex-wife be estopped from denying an agreement exists?

I entered into a Private Property Agreement with my wife as part of our Family Law process.

In order to gain 50/50 access to children etc, my ex-wife demanded and induced me into a Private Agreement that:

I refinance the matrimonial home into my name and provide her 50% of the equity upon refinance ($90k).

All matrimonial debt is consolidated into my name for me to pay with no percentage awarded against her even though the financial split, as determined by my lawyers, was 68/32 my way.

As a result, in performance of my obligations under that agreement and in reliance of that agreement that we would settle property by consent, I refinanced the house into my name, paid her $45k, assumed all debts into my name and paid all transfer and conveyancing costs.

My ex-wife has now said she will not honour our agreement and will not settle the property.

Can I estop my ex-wife as part of 'equity law' due to her denying an existing agreement? I have emails and text messages that support my position.