Uta has to move on, there's no other option because it's clearly shown that Kaoru only wants to go back to her pseudo happy life, those last lines in the recent chapter doesn't convince me that she cares about how Uta feels. To me, she only wants someone she can cling to so she can forget how messed up her life is, regardless their feeling. Intentionally or not, asking someone who you rejected as a whole to stay with you as if nothing happened is the most cruel thing one can do. Sure shit hurts as hell, but time got Uta's back (or everyone's back?!), move on and the wound will heal itself. Her moving on might also push Kaoru to confront Reiichi, to hear what he has to say and decide what to do on her own.