Why would an ex keep stalking me after saying she doesn’t want to marry me?

Me (M 23) and my ex (F) have had basically zero contact since April. She blocked me everywhere, so I’ve completely respected that and haven’t tried to contact her either.

The confusing part is that she still occasionally stalks my Snapchat stories. She also sometimes asks mutual friends about me. Recently, one of my friends mentioned me around her, and apparently she put on this whole “I’m fine, I’m happy, we don’t talk anymore” kind of expression. Then later she texted that same friend saying, “Please don’t tell anyone I asked/told you about this.”

And then she went back to watching my Snapchat stories.

I honestly don’t care that much and I’m not trying to get her back. I’ve moved on with my life, and from what I understand, she now sees me as doing pretty well/successful compared to how things were before.

But I’ll admit, sometimes I still miss her.

The weirdest part is that the last time I directly asked her if she would marry me, she said no. So if she doesn’t want a relationship or marriage with me, why keep checking my life and asking mutual friends about me?

Do you think this means she still has feelings, or is it just curiosity/ego/nostalgia? And has anyone experienced an ex behaving like this after completely cutting contact?