Steel, that was pretty damned insightful, thanks. Although I posed the question just as a general concept, it was and is related to my life experiences, of course. Not directly, not 'exactly', but related.
In that situation, there were things in AND out of the bedroom that affected my perception of that person to the point that the relationship ended.
In the case I was thinking of, it was the lack of that person's ability to adjust to my wants/needs/desires that was a a first clue. When someone spends their best efforts trying to get me off, but CAN'T, because they simply ignore the guidance and voluntary/involuntary signals coming from me, that's frustrating once, but something you can work on.
When it becomes a repeated problem, because they simply have "their way" of doing things, and they just keep hoping it will eventually work for me.. well, that's not gonna work. It's got to be a mutual learning experience, I think.
Plus, the "killer" in this situation was that the person simply didn't live up to their own words.. what initially seemed like a wonderful match turned out to be not so much so.
Ultimately, I say that it was dishonesty and a lack of empathy that killed it.. that person did not at first present themselves as they truly were, and over time I learned (of course) the true nature of the personality.....which was far less attractive than initially I was led to believe. And it did make them far less appealing as a sexual partner, as well as an emotional one.
The lack of empathy meant that even as I worked to understand the preferences and stimuli that worked for them, they didn't learn anything about me, and just kept doing the same things over and over.. which were, to me, not stimulating, and even off-putting.
Sex for the sake of sex can be tremendously enjoyable, but the partners that are good at that kind of thing are good at more than sex.. they read you, they learn what you like, and quickly! They don't ignore your responses just because someone in their past enjoyed something that they did, and they expect you to follow suit.
So.. yes, loving someone makes me more inclined to be patient and understanding about sex.. but it IS important to me, and I do expect them to learn what I like, so that we can mutually adjust things to our mutual enjoyment.
Make your own decisions, and own the decisions you make.