Hi Mashabo,
As someone who has recently been in your situation, I can confirm and validate your obsessive thoughts and the rollercoaster experience. Things DO improve, and the grief process is a pain in the butt. The one thing that could have been the key to a more direct route through grief would be to stay clear of him. I kept going back, literally and figuratively. The grief and all associated mind stuff is par for the course...
I never thought the pain would end...I am in a much better place, it does improve.