Sora and Yamato
Sora's crush on Yamato was a bit of a strange one. While she did like him romantically and was aware that he had similar feelings for her, she really didn't want to date anyone at that point in her life. She probably would have never initiated or accepted a relationship if her mother hadn't been hinting that she should do so.
Looking back she thinks her mother might have noticed that her sexuality wasn't totally the 'normal' and wanted Sora to choice a nice boy to settle for.
Yamato unfortunately did notice that she wasn't all that enthused to be dating him. At first he brushed it off because while Sora might be hesitant he was fairly confident she liked him too.
This confidence got a little shakier as time passed.
If given the time to come to terms with her feelings and pursue dating at her own pace, Sora's pretty sure it could have worked out, but she couldn't help often feeling reminded that she had felt pushed to pursue this relationship, making everything feel just a bit forced to her.
Finally, Yamato absolutely refused to be a source of her stress. She was, and always would be, first and foremost his precious friend. The break-up was only a bit tearful, they both knew it was beginning to strain, but they agreed to break-up on the terms of only pursuing such a relationship with each other again if both of them were ready for it.
Yamato didn't say he'd wait for her because, although he intended to, he knew it would pressure her all over again.
Sora can't begin to express how grateful this made her.
It was a bit awkward for awhile to see each other but then Jyou ended up dragging the hesitant Yamato to their study groups.
From there it was impossible to be awkward. No one can ever be the most awkward person in the room if Jyou's there, it's just impossible.
Their current friendship is stronger than ever and they have a deep trust for one another, there are of course some lingering romantic feelings and they like to toy with the idea of getting back together someday but neither of them are counting on it anymore.
Previous to getting together they'd always kept a gap between them due to being young and shy, although they had plenty in common and wanted to spend a lot of time together they'd been too scared of rejection. With the rejection gone and past there was no gap to stop their friendship from growing into a strong one.