Responses

I agree with you in most things but I do think it's possible for them to get together at some point, Kaoru isn't that much older than Uta and I don't think any of the characters are really in an emotional, maturity space to make a relationship work, so I guess it would be possible with a passage of time.
The thing I really want it's just for Kaoru to grow and realize that her relationship and the mindset she has in it isn't really healthy, even if in the end she is by herself and also for her to cut ties with Risako because she's a toxic friend.
I can't help but feel a lot of these "I hate Kaoru", "She's annoying", "I don't understand" comments are from persons with little experience or patience for adult concerns. Perhaps more background into Kaoru's life would help us better understand why she entered this marriage in the first place but people all over the world marry for convincing reason, under influential circumstances that look less solid later on, and it's not because they're all stupid and pathetic.
Marriage is a huge emotional investment. You've dedicated so much of your life to keep it together as a unit. Part of Kaoru already knows the answer to her question and she, quite understandably, fears the consequences. Nevermind the swirl of messed up feelings Uta's confession inspired. Idk what I'd do with myself if my spouse's teenage sibling, with whom I had such a wonderful relationship, confessed such feelings to me. *Worse* if even the tiniest part of me reciprocated it. Hello therapy lololol.
That baby move is, for sure, a bad idea and I hope it doesn't happen. But she grew up in a society that expects and even pressures women into making just that kind of bad decision so I don't find it particularly pathetic of her any more than I do of society in general.
I read this whole manga differently, tho, since I never wanted nor expected she and Kaoru and Uta to get together. How could Kaoru getting together with her high school sister-in-law be *any* better a decision than the things some of you find annoying and pathetic now? LOL. People are weird. (I include myself in that judgement.)