Vanilla is the real ntr. Honestly, think about it rationally. You are equiping, training, and raising the stats of the mc the whole game until he hits max level and beats the final boss for the sole reason of fucking the girl you like. All the hard work you put into the game, beating the early game hell, grinding for those high cost gear, and having to go through "that part". All of it has one simple result: the mc ending up the woman you love, who will eventually be fucked in every hole by him.

Got the perfect harem ending? Great. Who benefits? The mc. He gets to fuck the girls with his thick cock every night while your cheering on him touching yourself watching the act.

As a player , you are LITERALLY dedicating at least 10 hours of your life simply to make the mc perfect for your waifu to enjoy. It is the ULTIMATE AND FINAL cuckold.