Family Lore Clinic: Can my ex stop me from selling the former matrimonial home if the court has approved it?
Before I answer this, I will assume that by 'approved it' you mean that there is a court order stating that the property should be sold. If so, the order should specify how the sale should proceed (how the property should be marketed, how the sale price should be determined, who should have conduct of the sale, etc.).
If there is such an order, then the short answer is that your ex can't stop you from selling the property.
Of course, your ex may try to obstruct the sale, e.g. by refusing to agree the sale price, or by refusing to sign the sale documents. If they do, you can if necessary return to the court to sort out the problem - the court will expect its order to be complied with. For example, if your ex refuses to sign the sale documents, a judge can sign them for your ex.
As usual, the above is only a brief summary of the law. If you require further information or detailed advice, you should consult a specialist family lawyer.