For 95% of women in relationships it is not a control issue or manipulation. It is not malevolent.
Womens sexual desire is based on many things, and if just one of those things are out of wack it can make sex feel like a chore. Just because a woman can have sex "whenever" because they arent reliant on an erection, women can and often do suffer from the female equivilent of erectile disfunction.
Now how you you feel if you couldn't get it up, and then pressured, guilt tripped, and told you were using it as a control method.