When will people finally understand that there is no NTR with Eric? He has a girlfriend called Ann who he is cheating on but for it to be NTR Ann would have to be cheating on him.
Max, however, tries everything to have sex with Ann. If he succeeds, he is responsible for the NTR. Not Eric!
In some cases Eric even allows Max to join in or watch, which is not NTR it's sharing.
It's because they think THEY are the MC and that THEY are being cucked because a woman (real or fake) is having sex with anyone but them. It doesn't matter what the nature of the MC's relationship to the other characters is, just the fact that another male (or even female) character exists in a game is a "threat" to them.
Now if Eric tried to steal Olivia from Max while she was hanging out with Max and Lisa and is thought of as his girlfriend, THEN that would be NTR or at least attempted NTR. Though I doubt she'd fall for that with Max in her ear and probably knowing that he was trying to get to Lisa too.
Though none of that means that Eric doesn't suck.
He's the creepy asshole villain who wants to fuck everyone until he gets whatever his real goal is, which was the house (for whatever reason) in the original game.
He goes way too far to do it (slandering Max, blackmail, rape, etc), but so does Max at times. He (Max) has even already done stuff I wouldn't put in a game at all (messing with Lisa while she's sleeping is a bit too much) in this one.
Which is why I hate Eric as a character, he represents the kind of scumbag that no one should like or want to be like. All of that is why finally getting rid of him is always satifying, and it's why I don't want Max to be written like he's just a younger version of him.