Welcome back, Boy's Abyss, I loved to hate you.
Nothing to see here, just nuclear level mental illness. It's clearly not just repressed homosexuality, some commenters do not exagerate when calling Yume schizo, she even has the visual hallucinations. There's another chapter after this already so maybe we'll see, but I think there's additional trauma yet to be revealed about her. I think it would be in theme if she also has terrible parents. It may seem repetitive but that's basic psychology, her parents' couple is the first and most important model we have to form our idea of a relationship and love. So if it's not healthy, we'll look for similar patterns, no matter how fucked up they truly are, that's all we know about love until shown otherwise.
Same reason why at the same time, Aoi can't allow himself to love the other dude because the first time and last time he was vulnerable with someone he was betrayed. Why he's waiting for the other shoe to drop.
There's no sucess to be found in love if one never let the other be what they are, someone new. Sakura doesn't seem to make a difference between the very clear two phases of her relationship with Yume, the first one was a sweet meet-cute, but she held on when she started to bully her other a misunderstanding, not seeing she was being treated like her mother she hates treats her. Yume doesn't love her anymore, she's just using her like a vessel for her delusions.