When entering into a second marriage after a divorce with children of the first marriage there is always thought about protecting assets acquired in the divorce for the children of the divorce.
In Michigan a spouse is entitled to a certain portion of the estate of the deceased even if there is a Will that gives the spouse nothing. The spouse can take against the Will of the deceased.
If as a widowed or divorced spouse you wish the assets that you now have go to your children without being invaded by a new spouse you need to provide for this by creating a Will before the new marriage in order to protect your assets for your children.
If as an intended bride or groom, you are about to embark in a marriage to a person who has children by a previous marriage, an old Will may leave you in dire straits should the new spouse predecease you.
One has to be aware of the statute MCL 700.2301(a) which in large part says that if the Will directs the assets of the estate to or in trust for the benefit of a child of the testator who was born before the testator married the surviving spouse and who is not the child of the surviving spouse, then surviving spouse gets nothing. See In re Estate of Cecil C. Warren, Jr., deceased, unpublished Michigan Court of Appeals No. 262937.
In order to make sure that you are not caught by this trap after marriage, new estate documents are necessary revoking all prior estate documents.