In most states, if you have a will while you are married and then end the marriage, the will is automatically revoked. It's possible to leave an inheritance to your ex, but you have to write a new will that specifically states you are doing so.

Is a Will revoked by marriage?

When you marry, any existing Will is automatically revoked (cancelled) and becomes no longer valid. If you don't make a new one, then when you die the law of intestacy decides how your assets will be divided. Any marriage will automatically revoke your Will unless you're making the Will in anticipation of marriage.

Does a will made before marriage still valid?

Although a Will made before a lawful marriage or civil partnership is automatically revoked by that marriage or civil partnership, it will not be revoked if the Will is made “in contemplation”. ... Making a Will before marriage is important, and safer than avoiding making a Will, but there can be complications.