I'm at chapter 79.
They dropped the side characters halfway through minus when they don't relate to the romance. Like seriously I haven't seen the MCs kid or Ex girlfriend in ages & his friends only show up for exposition.
Is it because they received poor reception or the 'demon king' received overwhelming positive reception or was it all planned out? I'll never know. But yeah the 'demon king' is the best side character, though at this point he's basically a MC I guess.
Ero Wizard’s Research Journal