Chapter 69 ++Explanation For His Memory Lost++
p
The first accident was when Xia Tian's spiritual root was crippled by Liu Rouyan, Xia Tian had indeed lost a lot of memory, but as Liu Ying said in chapter 68, at that time Xia Tian could still remember Yu Suyin.
The second accident was when the real Xia Tian died, and his body was taken by Long Tian, and it was in this second accident that all his memories of Yu Suyin disappeared.
Note: Will his memory return? Actually, I never planned to restore those lost memories, because there would be nothing related to the real Xia Tian's memories anymore in the future. But who knows that I'll change my mind in the future :X.