Fredrik Backman said this quote

People in the real world always say, when something terrible happens, that the sadness and loss and aching pain of the heart will “lessen as time passes,” but it isn’t true. Sorrow and loss are constant, but if we all had to go through our whole lives carrying them the whole time, we wouldn’t be able to stand it. The sadness would paralyze us. So in the end we just pack it into bags and find somewhere to leave it.