first of all. it's weird referring to the boys as seme and uke when there's been not one sex scene in this manga.
secondly, if anything they used rio to get over their guilty feelings. he pushed him towards her and the other tried to date her as comphet because of the guilt of their attraction to the other guy. rio didn't realize until later, it's absolutely not her fault. it's not anyone's job to be aware of everyone's feelings.
the person who started this one sided relationship as a means to feel better about himself, was him. not rio who genuinely liked him
Exactly
Purr
I feel sorry for her and she deserves better but what she did to them is so bad.
She knew that it will destroy their friendship, she knew that she will hurt her beloved and her best friend. She prioritized herself that it ended everything they have.
If only she fights for her love fair and square then no one will have hard feelings but it's already too late and she also knew it.
The moment Seme left she breaks up with Uke cause till the end she doesn't want to give Uke to anyone else for her own selfishness. But she's tired of being in a one sided relationship.
She also can't move on cause she sees Uke still loves Seme and the moment Uke decided to confess and fo to Seme that's when she realized it's also her chance to be free but too late her life was taken.