The breakup for me was necessary for them to realize there love for each other without jealousy getting in their way. Plus Sijun got to go abroad without someone holding him back (i'm looking at you Keystone Romantic Combination)
Unrequited love always hits me in the feels... and when the seme finally likes the uke back I feel a great sense of satisfaction and he even treats the uke nicely. I wish all the semes are like this.
Sonoda is even hotter here