Why would a man hire a prostitute? I think I have been a good wife. I am open to anything in the bedroom, within reason. I can't imagine what he could get from another woman that I would not be willing to do for him, if he asked me. My husband has said he is sorry I found out about his secret life, but he has also said that I am taking this too personally, and it is not a slap at me or some kind of passive-aggressive criticism of our sex life. This may be moot since it looks like we are headed for divorce court, but I would still like to have an answer to my question.
It is hard enough to deal with finding out that your supposedly monogamous partner has cheated on you. Do you have an additional sense of betrayal because your husband paid for sex? It means he has broken two taboos rather than just one. That might make it harder for you to forgive him or rebuild trust. I will try to answer your question, but please keep in mind that I am not condoning his behavior.
Our culture has socialized women to look for sex in the context of an intimate relationship. Men are socialized to separate the need for sex from the need for love or tenderness. (Of course, there are women and men who don't conform to those expectations.) But it sounds like you and your husband have been taught to think about sex in two completely different ways. That doesn't excuse his behavior, but it might help you to understand why he can say this isn't personal.
While your husband may have a sexual need that he doesn't want to talk about with you, he doesn't necessarily need a secret like that to want an encounter with a sex worker. If he was out of town, he might have wanted sexual relief that was more interesting than masturbation. Hiring prostitutes avoids the emotional complications of an affair. A one-night stand with a colleague may not have been confidential enough. He may have wanted to receive pleasure without feeling that he had to be mindful of his partner's arousal and gratification. The thought of doing something forbidden may have been enticing. Or he may have wanted some variety in the woman's body type, hair color, ethnicity, etc.
Some married men who are clients of sex workers really do believe that they are not doing anything that will hurt their wife. They “protect” their spouse by keeping certain aspects of themselves away from the marital bedroom. Men who were raised to believe there are two kinds of women, virtuous ones and harlots, are especially susceptible to this false logic. To a man like this, asking his wife for certain types of sex (or even asking for sex “too frequently”) would degrade her, and then she would no longer be the type of woman he wants as the mother of his children.
Human nature is so full of twists and turns that none of the above may apply to your husband. If you really are interested in hearing the answer to this question, he's the only one who can answer it. But you might want the services of a mediator or couples counselor who can help the two of you listen to one another, creating a safe zone for potentially painful issues to be explored.
I hope you will think things over before you end your marriage. Don't assume that a divorce is the only solution. If the relationship was good until you found out about the sex workers he hired, why not give him a chance to explain? Maybe he has had a problem with your marriage that you didn't know about, something that could be fixed once it's brought into the light. I know many marriages that weathered infidelity and became stronger. I also know many that ended. Sometimes that is the best solution. If he has been unkind to you, or emotionally distant, or if you feel that this is compulsive behavior he cannot control, don't expose yourself to further pain. If he has been physically or emotionally abusive, you've got your cue to leave the stage.
A counselor who can listen to you, and you alone, might be very helpful. Friends get tired of listening, and they have their own agenda and opinions about what you should do. You might benefit from somebody objective who can be your advocate and help you walk through all these changes.