It sound like a big job, but it comes down to a simple equation:
Net Worth = Assets - Liabilities.

It does get a little more complicated than that, but not much. There are three categories of assets:

Joint assets
These are accounts that you have built together. They include joint savings accounts, chequing accounts, mutual funds and other investments, and any business interests that are jointly owned.

Your assets
These are accounts that you opened or owned before you were married and to which you have remained the sole contributor. Properties that you owned before you married are also included in your assets.

Your spouse's assets
These are anything your spouse opened or owned before the marriage, including RRSPs or assets inherited from family members.

Divorce is a federal responsibility in Canada, but the division of property between separating/divorcing spouses is under provincial jurisdiction and each province and territory has its own set of laws to cover these issues. You should be able to get basic information from your provincial government in the form of brochures and booklets about what your province's laws are dealing with property on the breakup of a marriage. If you have substantial assets -- or debts -- you should consult a lawyer.