Richard -
Firstly, it may be helpful to consult a family or divorce lawyer. Here is some basic info:
In Canada there is only one ground for divorce: Breakdown of the marriage.
Paragraph 8 (2) of the Divorce Act states that "Breakdown of the marriage" is established only if:
(1) the spouses have lived separate and apart for at least one year immediately preceding the determination of the divorce proceeding and were living separate and apart at the commencement of the proceeding; or
(2) the spouse against whom the divorce proceeding is brought has, since the celebration of the marriage:
(a) committed adultery, or
(b) treated the other spouse with physical or mental cruelty of such a kind as to render intolerable the continued cohabitation of the spouses.
The most common way to establish a breakdown of the marriage is to prove that the spouses have lived apart (have been separated) for at least one year immediately before the divorce judgment is granted and were living separate and apart at the time the proceedings began. That is, if you are using one year of separation to establish the breakdown of the marriage you can't begin the proceeding until after the spouses are already separated and can't finalize it until at least one full year of separation.
In plain english: You can file your divorce application with the court office on the date that you and your spouse separate. You don't have to wait for a year of separation to get the divorce proceedings started !
Sometimes one of the parties wants to get the divorce without waiting the year from date of separation. This can be done if adultery or cruelty can be established. Usually raising one of these to show a breakdown of the marriage will cause more upset and aggravation than it is worth. If the other side simply decides to deny the allegation you may have converted an uncontested divorce into a contested one and it likely won't be finalized within the year anyway. Almost all divorces begun nowadays show breakdown by one year separation.
You need to be aware that it may be possible to establish facts for annulment:
Annulment is the proceeding you take to end an invalid marriage. For example, a marriage might be invalid if one spouse was already married when he or she married the other, or if the husband or wife was under the age of 16. Sometimes, the financial consequences are different if the marriage is ended by annulment rather than by divorce.
If you were married outside of Canada, you should know that the question of whether a marriage is valid is determined by the laws of the place where the marriage occurred. So if the marriage was valid in your country, it will generally be considered valid in BC too. To get a legal annulment, you have to go to court, but you’ll need a lawyer to help you.
Some religions also grant an annulment. These annulments are valid within that religion but are not legally binding. Speak to your religious advisor or leader about this.
Now I'm no expert but, if you divorce, you are liable for her basic needs - food and shelter etc for three years as per your agreement when you signed the sponsorship forms. If she claims social asstance within that three years, you will be required to pay it back.
My understanding - and I stress the importance of consulting a qualified BC lawyer - is that if you have grounds for annulment as the marriage was in some way fraudulent, CIC may have grounds to deport/revoke PR if she was admitted to Canada based on a fraudulent misrepresentation. Again, please talk with a BC licenced professional to get the exact information and consider your options.