Legislation gives the same rights and responsibilities to civil partners and same sex spouses as are given to heterosexual spouses for all purposes for probate and wills. So what does this mean in practice?
a. Make a new will on entering marriage/civil partnership.
If you have a will and you then enter into a same sex marriage or a civil partnership, your will is revoked completely. So unless you make a new will before you die you will die intestate (without a will)
b. Make a new will when you separate, divorce or end civil partnership.
Divorce (on decree absolute) and the end of a civil partnership (on final dissolution order) both have the effect that any gift to or appointment as executors by the spouse or civil partner in the will made during the marriage or civil partnership takes effect as if the spouse or civil partner has predeceased the person who made the will.
Watch out! If there is only a formal separation or decree nisi only, this is not sufficient for the gifts/appointment to fail, so do make a new will.
The intestacy rules do not allow the surviving spouse of a marriage or the surviving civil partner of a partnership either of which that has been dissolved to benefit under the intestacy rules. Nor can any such person who is subject to a formal judicial separation.
When someone dies the solicitor needs to check the status of the marriage or civil partnership of the deceased and the status of any will and then apply the rules referred to above to determine who can validly benefit from the estate.