Hi...I'd just like to share that in my experience, emotionally unhealthy men cannot survive many days without a woman.
Emotionally HEALTHY men, sure. But every man I've known, whether friend, family, or lover, that's been emotionally unhealthy for whatever reason, has moved shockingly fast to put a new woman in his life.
This is no reflection on you, but should highlight that he's filling a void or a space, not that THE PERSON matters. When you realize that this means you too...it may be easier to emotionally let go.
I think you're still harboring some secret expectations from him rooted in hope...that's not in itself a bad thing, but you're set up for disappointment again and again. Maybe think a little about the dog situation. It feels like you may be inadvertently using it to stay a little more attached. (You could mail dog food money, order it online and have it shipped to him, ask a friend to drop some off, etc.)
I know this is hard!!!