Time. You will feel better with time. I lost my wife to cancer 6 years ago. She too was my only friend, literally the only person I really socialized with. I felt like I had died with her. I was devastated and did not care about anything including myself afterwards, though my life was over. But guess what? I'm perfectly fine now. I can think about her without pain and focus on the good times we had together. I'm actually happy as hell in life right now. You just have to keep moving forward and I can promise you 100% you will also be fine one day. It will happen faster than you probably think. Keep your head up for your kids, I don't care how hard it is you need to do that.