Charlie is a typical urban married man. He has three children (the third unplanned), a devoted wife, a senior position with a large accounting company in the city and of course, a healthy mortgage and a daily commute. He works long hours and has a demanding boss. He is sometimes called into the office in the weekend. The pressure is constant.
He coaches kids' hockey and tries to play two or three pick up hockey games a month with a group of old college buddies.
Charlie enjoys sex; his wife Connie, less so. She is very active in the lives of the children; a stay-at-home mom, she volunteers in the local PTA, is on the local library council and enjoys long distance running.
Through university, Charlie relieved stress through sex. He is what the average woman would call a hunk and he had no problem finding willing girlfriends before marriage. He and Connie met at college and married shortly after Charlie secured his first job. Before children, Connie was a willing sex partner. After children, like a lot of wives with a busy family life, she was often tired and when she and Charlie had sex, it was ho-hum.
Over a beer one night, Charlie confided to a friend. "The problem is, I need more sex than Connie does. I have no interest in cheating on Connie by having an affair though heaven knows the opportunity is there."
That is when the topic of escorts arose. Charlie's buddy had been seeing an escort for over a year. He told Charlie regular sex with his escort had made his home life better. His relationship with his wife was smoother as the tension declined with him not pressuring her for sex. He justified his use of an escort by the fact that he worked hard, was a good provider and relieving his sexual pressure was his reward for being a good husband and father. He said he was not emotionally involved with the escort; therefore he was not committing adultery. He loved his wife and enjoyed intimacy with her but it was not the same as when they first married. Their occasional lovemaking was usually over in fifteen minutes. With the escort he was seeing, she treated him like he was the best thing in her life. He felt like a lover, like he was needed, like he was a man. "The sex is great," he said, "But not the end all and be all'. 
Needless to say, Charlie put a great deal of thought into his friend's revelations and cheating in marriage. The need was there; the justification was there; his time could easily be accounted for and the expense was something he could easily handle. Could he justify using an escort in the same manner as his friend? A part of sex Charlie really enjoyed was oral. Connie had always been a reluctant partner in this aspect of their intimacy, both as a receiver and a giver.
To make the jump from faithful husband and partner to extra marital sex, Charlie had to justify his decision. Could he do as his friend had done? He did not want to have an affair. In his mind, that would be cheating.By paying for an escort's services, he was not breaking emotionally from Connie. He really enjoyed giving and receiving oral sex. Relieving his sexual pressure would make life easier for his wife.With less tension between him and Connie, family life would be smoother.Unlike his friend, he did not need to "feel like a man". He just liked sex.
At the end of the day, Charlie would have to come to terms with his conscience in making his decision.
To answer the question: why do men use escort services? Charlie and his friend have different reasons but use similar justifications. Research seems to indicate men use escort services for many and varied reasons with one reason not taking precedence over another. They include: 
I know what I am getting.
I travel a lot.
I want the escort to role play as a real girlfriend.
Men need sex more.
I was lonely and depressed.
There is freedom with an escort you don't have with a partner.
I can ask her to do things I would never ask of my wife.
I want to hang onto my marriage.
Does Charlie have a case? You be the judge.