If a wife abandons her husband and 2 children, how long will it take for the divorce to be processed in ontario after 2 years of separation has been served?

You file immediately after the 3 years, not 2. I did my own divorce papers, filed, and it was granted in court in a week, but it was a straight divorce, no children, no contest. However, you have children involved so will need a lawyer to sort out visitation rights, who is custodial, etc. Can't say how long it will take.