Well what is bad about 1000 years and I think betting on someone is the worst thing. And unlike the ML who is kind-hearted and stays with his decision the second ML is not someone much trustworthy. You can't say he won't leave you for another women. Also the ML loved Dam the most during his 1000 years of lifetime. He also cares the most for her placing her before himself.
Well the start of the relationship was nothing to be proud of. And I don't know in which aspect is he better than the ML. Except for the fact that he is a human which I believe ML will also become at the end of the drama.