If you read a lot of Netorare (NTR) doujins, in these situations when she has tasted that extreme level or "length" of dark skin pleasure, they can never go back. Even if they do, it's just to keep up appearance, the girl will look down on their former lovers in a mocking manner, considering their former lover's "length" or "skill" as pathetic, weak or inferior when compared to a "length" & "skill" of a superior male. Her mindset when her husband is humping her in the pic below will be something along the lines of:
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"Aww, he's slamming his hips into mine as hard as he can, how cute, still, THIS thing of his is nothing when compared to Master's that could reach me all the way to the end and r*pe my brains out, after all, Master is on a different level than you... huh?
Wait, did you just cum? Already? How pathetic.
But it's almost adorable how it twitches so desperately..."
Edit: Netorare doujins usually depict the guy who make the MC's lover succumb to him as a figure of peak male masculinity (Tall, black, extremely long "Stick", extremely buff or built, endless stamina, limitless sperm, a god of pleasuring women etc etc)
I hope this answers your question.