Meeting a great guy after a toxic relationship

After leaving my narcissistic ex, figuring out how to be a single mama and finding myself, whenever finding a new partner was mentioned I had a few dot points on what I would like in a man, or more so what I would not deal with again. There’s been a guy trying to talk to me for the last year or so, I finally gave in and we’ve been getting to know each other & spend time with one another and here’s the thing, he is just what I said I would like in a man, he is exactly what I prayed for and he treats me so damn good compared to how I’ve been treated. But here’s the thing, I just can’t do it. I honestly feel like he is too good & deserves someone that’s not me, I think too much about if I had this I’d deserve him more, if I was more like that I’d deserve it then. He is such a great guy and I feel like I’m so messed up from my ex I’d just ruin him. But I’m 100% over my ex, I see everything clearly and understand how things happened the way they did, I was so happy to finally leave & do better for myself. I’ve dealt with so much in my life and me and my girls deserve to be happy and have a great man in our lives, but for some reason I just can’t do it . Has anyone else been through this after such a toxic relationship?