What was your most painful/heartbreaking relationship experience?

when I was 38 I met a south african man,and the same day, he moved in with me. I just knew he was the one. We married in Russia 5 months later (I was working there), and had 9 years together. Then he died from cardiomyopathy aged 35. This was 7 years ago and I can never get over it. It was the best and worst relationship of my life. I could never repeat this with anyone, as I would not like to go through the heartbreak again.