The vast majority of American adults have failed to address their estate planning needs.
If you fail to plan, your wants and wishes have absolutely NO voice. However, the State you live in will provide a plan for you, which generally benefit the surviving spouse.
This can be a difficult pill to swallow for the surviving spouse and the stepchildren, who are your children.
The good news for you is that proper estate planning, with a will or trust, can avoid the frustration and potential hurt that is almost assuredly going to arise in such scenarios.
See Amy Ziettlow & Naomi Cahn, Step-Families and Estate Planning, Family Studies, October 6, 2016.