He sounds like he's very ready to move on. I'm sure he did care at one stage, but he's now older and starting to make decisions for what he'd like his life to be like. This is totally normal for a man of his age. Unfortunately, the current situation isn't where he wants to be or continue doing.
I have to say that from my own experience, it's not unusual to have no regret or sadness when deciding to move on. Likewise, I totally relate to the feeling of a weight being lifted. I will also add that some people do their mourning for the relationship while they are still in it - so by the time they are ready to leave, they can do so without sadness. The sadness has already been processed and left behind.
Think about it this way, what is there to be sad about when looking to the future? The future is an open book - and there's no sense dwelling in the past.
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.