I feel like it's fhkdgn like, a minor tragedy for Aoyama, but not for Ong, if that makes sense--Ong pretty much had the rest of her life doing other things while Aoyama seems to have carried a bit of a torch in a way that reads (in yuri terms) tragic side character. And hmm my read is that it's not so much a couldn't/shouldn't as much as it is a can't/shouldn't (Aoyama) and a won't/shan't! for Ong?? if that makes sense.