Quite common, you're not alone! I've been through break-ups but not after 10 years!
How it ended is important. Mutual thing? Was cheating involved? You fed up with gambling/alcohol problem? Prison? Or just the feeling went away?
Anger is normal because no one want relationships to end, but try to remind yourself that you are better off alone than with someone who makes you miserable. Many other people are worse off, too. Like abandonment, or violence, or even death of a loved one.
Try to change your perspective. It'll get easier as time goes on. Just try to keep the good times with you, and accept that you aren't going to be okay with it all the time, but it is a fact you must deal with. And even though he might seem together about it, he'll have his moments, too.
No one knows what the future holds, but it could be much better than what you've seen so far.