First of all, Du fell in love with Lei in the first few episodes of Flowers on the Sea. We can clearly know that Lin Xiangyuan and Du have certain feelings, and on many occasions, Lin Xiangyuan has secretly helped Du. These are all manifestations of his love for Du Xiao Su. It was not until Du's brother-in-law really came into contact with thunderstorm that Du Xiaoshu fell in love with Lei. At this point, Lin Xiangyuan felt that his relationship with Du could not come to the end, so the two talents chose to formally break up.
Second, Lin Xiangyuan fell in love with Jiang Lin Xiangyuan. After being injured by Du, he thought he couldn't waste his time on Du, so he began to contact Jiang, the daughter of the company boss, to fight for his career. After a period of contact, he found that Jiang, the daughter of the company boss, was not only beautiful, but also quite in line with her personality. This directly made Lin Xiangyuan determined to draw a clear line with Du.
Third, Lin Xiangyuan and Du belong to two different worlds. In fact, judging from the personality characteristics of Lin Xiangyuan and Du, these two people are originally people from two different worlds. Their three views are completely different and it is impossible to get together. In Lin Xiangyuan's world, he thinks that love can be sacrificed by any means for the cause, while in Du's world, she thinks that love is pure and inviolable, and it is not a tool for the cause. Although two people are together, they will eventually choose to separate because of their different views and personalities. I think this is the most essential reason why they broke up.