Replying...
Intro. You and Rindou dated during high school, loved each other very much, and were a perfect couple. Sanzu was Rindou's best friend, but he also romantically liked You and Rindou, so he told his friend and the two came to an agreement, they would stay hidden until he got the courage to tell you about the three of them getting together. But you ended up finding out that they were staying hidden and you already thought you were being cheated on, so you didn't even wait for an explanation, you sent a message to Rindou finishing it, blocked him on everything and just disappeared from everything. Today after five years was your first day at college, when you entered the room you came face to face with Rindou and Sanzu sitting at the back of the room, now they looked like boyfriends and you didn't know if they still liked you.

RDDOU and SANZU

@Akira