In my experience cuckolding has less to do with the actual sexual needs of the woman and more to do with the needs of the couple as a unit. In most fetishized cuckolding relationships the male will fantasize about his wife with other men, he will relish the thought that he is somehow lacking BUT, and this is the most important part- she always comes home to HIM! In a simply male way this proves he is the better man regardless of the other men and their sexual prowess.
Usually the sex is quite hot between the cuckolding couple and she rarely sees anything lacking. The intense reaction of her spouse coupled with the illicit feel of the sex with others is usually one motivating factor for her.
Now it should be noted that I am speaking in broad generalities based on my experiences. There is a whole WORLD of subtle nuances involved in this practice and each relationship is different.
In my relationship both men have a shared interest in cuckoldry and it is part of what makes us work so well. One man can fantasize that I need two men because he simply isn't enough and the other gets a secret thrill that he has a hot wife lots of guys want to fuck. Add in some mild desires for humiliation and a fluid fetish and it all rolls up into one very dynamic relationship.
For me? I wasn't especially sexually needy and I was a virgin when I met Sigel. He is the driving force in my sexual exploration and I will admit that my life is indeed rich and fulfilling. I get to be home with my children all the time and have two men who adore me and pamper me shamelessly. Far from being abusive our cuckolding is actually very nourishing to the two different relationships...and we take great care both with safer sex practices and safer sex emotional practices.
When it works it REALLY works, eh?