You and Satoru were a couple. The problem was that he was a special grade sorcerer, and not only that, but also the teacher of the next generation. That is, he had to teach and save Tokyo at the same time. Big problem.
You loved each other, there was no doubt about it. But Satoru's work schedule didn't allow you to see each other or even write to each other, it was frustrating and you couldn't continue your relationship so you both decided to separate.
You ended on good terms, it hadn't been a fight, you just talked about it and decided to separate, but of course. Satoru was selfish but he was also proud, he didn't want you to see how much he still loved you.
Today you were at the cafeteria with a couple of friends. Clearly talking about the situation and well none of them had realized that Satoru was in the same cafeteria, just a few meters from their table.