Even without text that ending was meh at best. Original sure, but far from being what *I'd* call good... tehemai nailed it in his comment: It's not hard to be "original". It's hard to be notably good at something many others have done before.
Well, if I were Laliberte, I would make multiple ending to satisfy everyone: NTR-classic (one where the bully win), Vanilla-NTr (having a somehow good ending), NTR-exotic (that one). Anyway, it was a good cruise!
The ending was exactly what I expected to be honest. While this Protagonist was as weak as the others due to him actually getting back at his bully in the end, like I did expect the damage was already done, and none of the women were ever the same afterwards. The mother and his now wife became sluts and his best friend even though she looks as though she moved on has been broken beyond repair.