I can see a lot of people don't really understand this manga. There is a reason why the coworkers keep trying to dissuade Ishizuka from confessing to Tachibana and it might not be apparent to people who are non-Japanese, but it's very clear to everyone around them that things such as age and status do not match. Ishizuka is very romantic for a Japanese man, he even bemoans something to the effect of "is love not enough?" and while that may resonate with western audiences, it's intended to come off as immature in this context.
The turning point in Ryo's confession seems to be the thing that most people are not understanding or did not catch. Please go re-read it again. He is doing, relatively well, or at least not facing a huge wall of resistance until after he mentions Yuzuki-sans child. The way he brings it up is pretty much the most horrible way to do so. He literally says in Japanese "子供も関係ない" which translates to "Kids don't matter".
Uh... not the smartest thing to say to a single mom. Just look at that panel and the look on her face when he says it. It's like he threw a gallon of cold water over her. Basically, the dude was doing alright until he unintentionally tipped his hand and showed Yuzuki how non-seriously he was taking this proposal of his to "date with the intention of getting married".
Also, before anyone tries to defend this guy by saying it was a slip of the tongue or that he didn't mean it that way - it's literally written in kanji that he totally did mean that kids don't matter. There's very little ambiguity in that sentence.
Anyway, point being, he set his hopes on fire with that one statement. Pretty much anything lame like "I love kids!" or something would have worked better for him.
Honestly, the entire setup is just very, very Japanese. It reminds me a lot of a very 80's coming of age type mens romance, like Maison Ikkoku. Hell, except for the addition of the child to the plot, the set up is almost exactly the same. I think it's pretty good. I hope it lives up to the epicness of some of those 80's/90's mature romance manga. There is a lot of potential here. Hell, I can pretty much predict how this manga is going to go and I'm looking forward to seeing it because it's been damn near 20 years since the last time I saw a good one pulled off.
Hats off to the mangaka and I'm going to go look for more raws now...