He's already moving in with her?

So me and my ex broke up close to 3 months now..he started dating this girl 2 months ago. We live in the same city, not small but "small in a sense" so people still ask me about him and so forth. Yesterday I found out that he's moving in with this girl he's dating and my mood immediately depleted, I felt like bawling. We dated close to like 8months, while we were dating we apartment hunted together even though I ended things before that came to anything. I don't know why but I'm upset and furious at the fact that he's moving in with this girl.😡 and then it's also hurtful. I don't know I just feel like he's moving too fast..I broke up with him because he was uncertain of his feelings with me and just wasn't gonna stick around with a man who doesn't value what we have but now to know that he's at this level with this girl already after two months is very hurtful, after three months I'm still trying to get over him and trying to heal from letting him go and what we had, but for him he's already moved on so quickly. Am I wrong to feel this way? 😔