Is it really possible to move on so fast?

We dated for 7 years, lived together for about 6. Distance broke us up at the end of October and we have been on and off NC (currently on). I know he’s moved on. He told me there was a girl who wanted to date him while him and I were still talking about reconciling in the future when we can physically be together. He told me he said no to her because he wasn’t ready. He was supposed to call me one week to express how badly he wanted us to work out in the future but we never ended up speaking bc it seemed like he wasn’t giving it the importance it deserved. I then set an ultimatum (which I never do) and said if he doesn’t call me that day then to not bother calling ever. I’m about 90% sure he’s with that girl now.

I guess none of that really matters to what my main question is; after 7 years, is it really possible for him to have moved on completely? Is it possible for him to not think of me? Did our relationship just mean more to me? I just truly can’t process it. I get that he may have been grieving while we were still together, but still. To be with someone else already after 7 years, and after saying he still wants us to work in the future - I just feel so lost and can’t understand it. I know he has avoidant tendencies but I can’t understand it because I’m anxious. Anyone have some insight?