Married spouses often hold real estate in joint tenancy, as opposed to tenants in common. The principle of joint tenancy is that both parties own the property as an undivided whole and, immediately upon the death of one, the surviving joint tenant acquires an undivided 100% interest in the property. The property never falls into the estate of the deceased joint tenant, so the provisions of the deceased’s Will aren’t relevant.
Joint tenancy is to be contrasted with owning property as tenants in common, where, after death, each owner’s respective interest in the property devolves to their individual estates and gets distributed according to the terms of their Wills, or the laws of intestacy.
In cases where an individual has children from a previous marriage who want to inherit from their parent’s estate, these children might argue against the operation of the right of survivorship with respect to a jointly-held asset like the matrimonial home.
It’s possible to sever a joint tenancy. For real property, you can transfer the property from yourself to yourself, thereby constituting notice on title that you have unilaterally severed the joint tenancy. You can also argue that the parties no longer intended to treat their ownership of the property as an undivided whole. This intention or conduct must be mutual (unlike registering a severance on title which is clearly a unilateral act).
In Hansen v. Hansen, a married couple were in the process of separating and dividing up their assets when the husband died. The husband had already removed his wife as a beneficiary under his Will. The wife, who had moved out of the matrimonial home, argued that she was entitled, by right of survivorship, to ownership of this house.
The husband’s children disagreed, claiming that neither party considered the house to be owned in joint tenancy following the separation. The Court of Appeal found that considering the parties were negotiating the division of the family assets at the time of the husband’s death, they both intended to divide their interests in the home. By their mutual conduct, therefore, the joint tenancy had been severed. Based on the facts of this case, it might be hard to argue that any joint tenancy survives a separation.