He's just a normal guy, living a normal life. Ground by the corporate machine, no energy left for being lovey-dovey. Two years after marriage, so a lot of magic is gone. He is a bit of a dick at times, but so are most people. At the same time, he seems to be supportive - letting her stay at home and telling her not to let his/her mother pressure her. He seems genuinely happy about going back home to his wife and being with her. He also seems not too keen on having children, but he is going along with it because Yukako said she wanted it + societal pressure. From what we've seen up to this point I can really empathize with him.
Chinami looks to be pretty torn between her lingering feelings for Yukako and feeling of betrayal. I can see it going both ways, depending on future chapters - she can try to steal Yukako away, or destroy her relationship. Or a combination of both.
Yukako is obviously at the center of "fault". By the time she married, she must have confirmed she is not attracted to men, so she basically went with the flow of societal expectations when the guy proposed. Unlike "Run Away With Me, Girl" or "Even Though We're Adults" we don't even really see any kind of connection between them so going with the flow is probably the most apt description. Going to the reunion seems kinda out of character for her, since she knew she will probably meet Chinami and cause herself and/or her pain, but that could have been a kind of cry for release from her situation. And now she is a coward, who could never make a serious decision in her life, pushing herself into a situation where she will likely have to make a very dramatic decision.
This feels like a series where no one will end up happy by the end. And someone might end up dead. Pretty good read nonetheless.