Dude could've busted out the Streisand effect: fighting it just pours gasoline to the fire. Just make a sad face and talk about your continuous lapse in judgment, and your audience will move on. Some will still shit-talk you, but it will die down.
He was spot-on about how he disarmed the conflict. Even if you're deeply hurt by insults hurled at your craft, firing shots back won't do you much good. I think they were really close to saying things to eachother that one can't take back.
I do wonder about the ideal solution to their problems. They both want eachother all to themselves, but for that to happen, Runa has to learn to rely on others more, and Hayato needs to draw clear lines between his work and private life - so she feels less like the whole thing is a timeshare.
In all likelihood, Runa's form of self-reliance is her response to a string of relationships with family and others, that failed her. Persuading her otherwise is a lengthy process, because even decent and caring people make mistakes all the time, but money rarely lets you down. Maybe if you launder it or don't pay taxes on it, but that's it.
What makes it excruciatingly hard on Hayato's part, is that he probably has no idea how deep her issues run, and what exactly makes her tick. It's hard for people with loving parents and a stable support group to truly understand why yours isn't worth a damn, and won't be, no matter what you do. Or how bitter they can be, if you try to shake that one pillar of stability in their life.