If sending this will give you closure and you honestly don't want to hear from him again then I think you should send it. If you really don't want to hear back from him then put "Do not reply" and then you won't have to worry about getting a response. But go through the possibilities of what might happen...getting a reply, not getting a reply, getting a hurtful reply. If any of these might cause you more pain then you seriously need to decide if it is a good idea. Good luck