That's why I called his relationship with Tsubasa an organic part, because it was by his choice that he got involved with her, and she, quite realistically, had her own circustances as to why she did what she did.
But:
The blonde girl just so happen to walk into the same cafe Tsubasa and Kaede were having a date in
Kaede's bros just so happen to have been around to comfort Kaede when Tsubasa did what Tsubasa does
Kaede just so happen to overhear the argument between the asexual classmate and his girlfirend without benefits, which led to the conversation about normalcy, which became the theme for the following chapters
Kaede just so happen to walk into the cafe owned by an extremly patient lady with her own baggage of drama and ideas of normalcy
And, well, what's about to happen