Better to leave him than to lead him to believe there’s a possibility of another chance. You said it in this post. There’s nothing left. So go.
I agree with kiyanna, you’ll probably be more happy in the long run and it sounds like your hoping for something that just isn’t there anymore
Don’t leave something long term for something temporary. This could just be lust and he’s giving you the attention you crave. But, how you said theirs nothing there with your husband so maybe it’s time to leave, but don’t go diving head first with the other guy, just have fun with him, because that’s all it could be.
Good place*