He actually knew that when Monica bumped into him and Patsy, she was very upset. However, she could quickly regulate her emotions and let go of a relationship. She would not let herself dwell on it, unlike him, who would never let go.
That was why he went to look for Monica after three months.
He went to wait for her at the school gate. He did not want to pursue the matter between her and Michael anymore and decided to tell her about his relationship with Patsy.
He admitted that he was deeply involved in the relationship, so he did not want to lose it.
With that, he waited at the gate for a long time until Monica finally showed up.
However, Michael was also there.
The two of them walked out of the school gate hand in hand.
He remembered that he and Monica had never been so close back then.
Of course, he was the one who rejected Monica from getting closer as he believed everything could wait until after they got married.