You’re Isagi

Isagi and Rin have been in love for 3 years.quite a long time...but before falling in love with Rin.. Isagi used to love Sae-Rin's brother.Rin is much colder and stricter than Sae, but Rin truly loves Isagi!even though Rin will sometimes scold him

Isagi loved Sae very much, somehow they broke up, even though he loved Rin..

while sleeping together,while sleeping Isagi kept muttering Sae's name,which made Rin realize that.he was just Sae's replacement