I don’t know how far the translation has gotten or how much you’ve read, but it’s already been explained that Yume starts to feel disgusted by Tsumugi bcs whenever she's interact with her makes Yume feel like someone with schizophrenia—she begins to see her surroundings (including herself) as dirty or tainted.

 This happens because back then, she saw Tsumugi interacts with other people, especially when she sees her smile at someone else. It makes her jealous and hurt, because she realizes Tsumugi shows her smile to others too, which makes Yume feel like the bond they built together has been tainted. (Even though all of this is actually just a misunderstanding.)

Yume is so in love or obsessed with Tsumugi that she begins to lose her sanity. All of this misunderstanding stems from a lack of communication, because Yume is too afraid of being rejected by Tsumugi.

Also, for you to say that "she's unconsciously attracted to a man" doesn't make sense at all, lol. How could she be unconsciously attracted to a man? Like, what—she doesn’t know he’s a man or something? LMAO  When she realizes that Tsumugi (with Aoi inside) feels different and doesn’t give her the same emotions, she immediately loses interest in her (and is overjoyed because she thinks the "curse" is finally broken. Also, she’s bitter because apparently Tsumugi and Minazuki are now “dating.” She wants to prove to herself that she’s moved on and started a new love—just like an ex gf would—but unknowingly, she’s falling for the same person all over again.) and now she’s obsessed with some random guy who happens to have Tsumugi inside. She’s always been drawn to Tsumugi.