Unpopular opinion: reiichi isnt a bad person
He's made some bad choices, aka even getting married in the first place, but he hasn't cheated and has only spoken to his ex for advice. He didn't even sought her out she just was there naturally from.work. He didn't want to hurt Karou and has done what he thinks is best for her, we know that's obviously wrong but I don't think he's a bad guy so it's weird that everyone on here is like OMG REIICHI IS THE DEVIL I HATE HIM. I hate the "evil/dickhead man" in Yuri trope so I'm glad we don't have it here
He may not be a bad person but he's a terrible husband, and that's easy enough to hate. I can't imagine marrying someone fully knowing that I'll never love them the way they love me, who would deserve that? And he's basically like "If I never love you more why would that be a problem in our marriage?" That's pretty cruel to me, though I can accept that people value marriage differently. It's just if I were in her shoes I'd be extremely hurt and in a rage.
Though I'll admit, since it seems she had her doubts all along, they clearly weren't being honest with each other their entire marriage so this mess isn't solely on his ginormous shoulders alone. Only mostly.
Also working and meeting with your ex and never mentioning it to your spouse is wrong as heck.