I am 29 years old, single, no kids, and most of the time lonely. I live in an environment surrounded by peer pressure. This is not a perfect world. Even media and entertainment promotes sex. The people around me talk about sex often. When I'm lonely, and my budget allows, I have sex with a prostitute. I do wear protection. It's just that I don't understand if having sex with a prostitute is bad when you're single. I do know some married and people in a relationship who do it. I'm not in a relationship, but I still take care of my business responsibilities. I'm not committing adultery and I don't covet my neighbor's wife and goods. Is there something wrong with me? I may not be an active Christian but I really do need some help.
It seems obvious to me that you at least suspect that something is wrong, else why would you be asking a preacher? But let's move the topic out of speculation and look at what God said.
"Don't you know that your bodies are members of Christ? Shall I then take the members of Christ, and make them members of a prostitute? May it never be! Or don't you know that he who is joined to a prostitute is one body? For, "The two," says he, "will become one flesh." But he who is joined to the Lord is one spirit. Flee sexual immorality! "Every sin that a man does is outside the body," but he who commits sexual immorality sins against his own body. Or don't you know that your body is a temple of the Holy Spirit which is in you, which you have from God? You are not your own, for you were bought with a price. Therefore glorify God in your body and in your spirit, which are God's" (I Corinthians 6:15-20).
Prostitution has long been condemned in the Bible. "There shall be no prostitute of the daughters of Israel, neither shall there be a sodomite of the sons of Israel. You shall not bring the hire of a prostitute, or the wages of a dog, into the house of Yahweh your God for any vow: for even both these are an abomination to Yahweh your God" (Deuteronomy 23:17-18). The book of Proverbs has numerous warnings against prostitution, see the lesson "Prostitution" for details on why it is wrong.
The basic problem is that the act of sex only belongs between a husband and a wife. "Let marriage be held in honor among all, and let the bed be undefiled: but God will judge the sexually immoral and adulterers" (Hebrews 13:4). The word "bed" in this verse literally means the act of sexual intercourse. In marriage it is honorable, but when the partners are not married to each other, it is an act of sin. The older English word for having sex when you are not married is "fornication." Fornication is usually translated as "sexually immoral" or "immorality" in newer translations as the word "fornication" has fallen out of favor. Therefore, each time you've gone to see a prostitute, you committed the sin of fornication.
Paul argued in I Corinthians 6, that when you, as a Christian, join yourself with someone who uses sin to make money, you are bringing dishonor to the Lord. You call yourself a Christian, which means a follower of Christ, but then you pay someone for the "right" to commit a sin with her. That doesn't make sense. God isn't going to support such a person.
Also, Paul argues that Christians are the tabernacle, or dwelling place, for God in this era. Just as the tabernacle of old was to be kept undefiled, so too, Christians should be keeping the current tabernacle, their own bodies, undefiled from sin. If we defile ourselves with sin, the Spirit of God won't be with us.
Looking back at your note, I found a very sad point. You claim to be going to prostitutes because you are lonely. But for all your visits, you call yourself a lonely man. Look at reality. Does a prostitute really care about you? To her, you are just a paycheck and food on the table. "For a prostitute reduces you to a piece of bread" (Proverbs 6:26). Sure, she gives you lots of attention for a short while, but it is because you are paying her to do so. That isn't a cure for loneliness. "But if they don't have self-control, let them marry. For it's better to marry than to burn" (I Corinthians 7:9).
If you want a true companion, find a wife. That is why God instituted marriage. "Yet she is your companion And your wife by covenant" (Malachi 2:14). Quit settling for cheap substitutes which don't solve your problem and destroys your soul in the process.