Things can get difficult with an estate plan, especially if it includes a trust, if you and your spouse have separated but have not yet gotten divorced, according to the Canadian newspaper The Globe and Mail in "A warning for couples who have split but not divorced."
Canada and the U.S. have similar laws in the area of marriage, separation and divorce.
The law will not assume you want a spouse from whom you have separated to not inherit under your estate plan.
Why? Until a divorce is finalized, you and your spouse can always get back together and courts cannot divine what you intended.
The solution to this problem is to see an estate planning attorney when you separate from your spouse.
An estate planning attorney can advise you on creating an estate plan that meets your unique circumstances and provide advice on keeping the plan up to date, should a separation or divorce occur.
Reference: The Globe and Mail (Sep. 12, 2017) "A warning for couples who have split but not divorced."