People who complain about NTR crack me up. Sure seeing some dude cucked is sad and all, but in this game these girls aren't even "yours" to begin with. They don't even love the MC of the first game, they're just horny.
They literally equate sex = love and that's not even the case, that's fucking childish logic right there. Even IF the girls in the "NTR" (not even NTR) say something along the lines of 'I don't even love him./You're better than [MC].', that's not even NTR still. It's not explicitly said to YOU THE PLAYER that you and the girls are dating, married, or have plans to do either. Sure it's them being a bitch but YOU CAN LITTERALLY FUCK THEM ON A MISSON WHENEVER YOU WANT. Get over it, Jesus Christ.