I came into a family when my mother remarried. My sibs and I were 26, 20, and 18.
We will inherit our stepfathers assets. I mean, he has been our family for almost 30 years. He is the only grandparent my kids have on my side. My mother died years ago.
It's great that you have a bond with your stepfather even though you were all adults when he remarried, such a good bond that he's even a grandfather to your children.
Most people I know don't have a bond at all with the spouse their parent married when they were adults. In that case I don't think it would be strange to not leave them anything in a will. I know my partner and I don't have that with our parents's spouses and beyond sending christmas cards and visiting maybe once a year if we're in the area I can't imagine we'd keep in touch after our parent dies. Of course it's different for stepparents who helped raised you or you were very close to, or who have even adopted you, but that's a different situation. Still you should treat stepchildren and stepgrandchildren equally when it comes to christmas, birthdays etc even if there's not much of a bond.
I had never thought before about the possiblity that my parent would leave anything to his spouse's adult children, but if it turns out that they did, I would feel a little bit slighted (although honestly I'm pretty sure I've been disinherited either way, which would legally only give me a claim to a small part of the money, not to any physical items). I wouldn't mind if they were left money,or even all the money, but I would care about heirlooms and items of sentimental value, especially items that came from my family of origin or relatives that were dead 20 years before he even met his spouse. I know some of our family photos have already ended up with non-family and somehow that feels not only unfair but also as a breach of my privacy.
