This is going to take some explaining

Clary and Jace had been friends all their lives, but when Simon Lewis came around, Jace slowly got edged out. Years later, Jace is just sitting in a regular coffee shop when Clary walks in. She take his breath away, then he notices her tears. What just happened, and what has Jace missed all these years? *this isn't a sad story, but there are a few lows for the characters.