AITAH for not including my future stepkids in my will?

I (45M) am engaged to my fiancee (39F), who has two kids from a previous relationship (13M and 11F). We’ve been together for three years, and I really like her kids, we get along great. But just to be upfront, I have two adult kids from my first marriage, and they’re my priority.

The other night, my fiancee brought up the idea of updating my will to officially include her kids. She says it’s important to her that her children “feel like part of our family” just as much as my own kids. I told her honestly that while I care about her kids, I don’t plan to put them in my will. I’ve been clear that I worked hard to build what I have specifically to benefit my children, who I raised and have been there for their whole lives. I’ve only known her kids for three years and feel it would be unfair to divide my estate with children I didn’t raise or even meet until recently.

This conversation turned into an argument, and she accused me of treating her kids as “less than” and of not being serious about us as a family. She said that by marrying her, I should be treating her kids as my own. But to me, marriage doesn’t automatically mean my entire estate should now be split four ways.

I told her that this isn’t up for debate. I do love her and her kids, but I don’t feel comfortable putting them in my will. She’s barely spoken to me since, and now I’m wondering if I’m being too stubborn about this.

AITAH?