Lost my boyfriend suddenly and unexpectedly

Hi All
I lost my boyfriend suddenly and unexpectedly on 9th January this year. Since then I have felt so lost without him. He was my best friend, my rock, my everything. Its like he was here one day and just gone the next. I have never experienced grief like it. From what started off as a normal day to the worst day of my life. I will never forget that day. I was just in work when the receptionist at my work place said that my Dad had been on the phone. I immediately thought that it was my mum taken ill. Then she said he was in the family room, so I went in there to find my mum and dad and my partners older sister. I immediately asked what was going on and I said its David (my partners name) isn't it? I thought they were going to say that he had been in an accident on his way to work and had to go to hospital. Nothing could of prepared me for what was going to be said. I just froze with shock wondering if I had heard that right. I said 'Please tell me this isn't true', but the look on their faces said it all. The rest of that day was a blur. I just went into autopilot, couldn't get my head around it, he was fit and healthy, walked and cycled everywhere, went to the gym three times a week. 'How? Why?' I asked. Nobody could get there heads around it. He was 43 years old. Received the results of the post mortem a week later. It was inconclusive, so had to go to autopsy. The funeral was still able to go ahead. Even though the funeral was two months ago, I still cannot come to terms with his sudden death. We had made plans for our future and it feels as though the rug has been pulled from underneath me. We planned to meet up that weekend. Nobody knew he was going to die. HE didn't know he was going to die. He hadn't been ill, it happened totally out of the blue. Received the results of the autopsy three weeks after the funeral. It was a heart attack caused by a build up of plaque within his arteries. Even though I was told he didnt suffer it still hasnt brought me any comfort. Life is so unfair, why did it have to be him? I really can't go on without him.