There is just something right about this series. The MC is banging bitches and helping his naive OP bro at the same time. Its like he's bringing balance to the force.
This kind of hentai heals the soul. Not NTR. Not Rape. Not Blackmail. Not Drugs. Just a dude helping girls deal with their stressful lives by dicking them good.
I don't think this counts as NTR. The guys gone for half a year? No calls? No visits? If you abandon a car in the middle of the street with the keys in the ignition and motor running? You should expect someone else to drive off with it.