He left moved to Alberta

The only way to dissolve your marriage is by way of a divorce order. You are legally married. Your status is separated, as of either his relocation to Alberta; when he started paying child support; or when you got a new mortgage. Assuming, he did not provide his income information when paying the $1800 per month, you should have sought and requested his information. He obviously acted completely contrary to the child(ren)'s interests in not paying any support. Retroactive child support may be claimed provided the child(ren) are dependents and therefore in need of child support. You would need to enforce the order to ensure payment. You may seek counsel to discuss the calculations of a lump sum amount. The real estate lawyer may be directed to disburse the sale proceeds pursuant to your respective instructions, if jointly owned, or simply to the owners of the property. Equalization of matrimonial property has a limitation of 6 years. The disbursement of sale proceeds is not necessarily an equalization issue if the house is jointly owned.