Newsflash: If your son looks like a shitty man, and you think his gf/wife whatever "made" him shitty. HIGH chances are that the guy was already shitty!
Gai is a nice kid, already, yes... but good lord, his mother is definitely something else... stop sheltering your offsprings, gdi! Pretty sure that environment at home is what made Hibiki the way he is, and is EXACTLY what Gai is running away from. It's just the mother looking for an excuse of "boohoo, my sons were good boys! It's that woman's fault they are being like this!" JFC.