It is really hard to explain. A willing spouse is NOT the saem as a desirous spouse, not even close. I like to think of it in terms of something my wife LOVES to do and that is shop. I go shopping with her because I am willing to shop. After doing this for many times, she would prefer NOT to shop with me, it's just not fun. So she now basically shops with her girlfriends. She has found a DESIROUS partner for shopping, and it results in a much more shopping happiness. Apply that to sex, she is WILLING to have sex, but so are hookers. There is no real connection going on, I am a "CHORE" not something she REALLY wants to be doing. I don't care what the activity is, if the person you are with even HINTS that it is not what they really want to do, it spoils EVERTHING about that activity.
But even beyond that, HD women ACT differently OUTSIDE the bedroom. This is MORE important than what happens IN the bedroom. Desire effects:
Flirting Playfullness (rather then serious) Happiness Handholding Kissing, especially with tongue Oral sex Passion Intensity of the relationship About 100 different and pleasureable chemical changes in the body physical teasing Horniness The abiltiy of the LD spouse to show love (this one is key) and even the length of a persons life.