Whenever people say they don't think the Ten Commandments are of any use today, I often wonder if they've ever actually read them, because if they did, they might change their minds. (You can read them in Exodus 20 or Deuteronomy 5.)
Let me explain. The Ten Commandments is divided into two parts. The first commandments deal with our responsibilities toward God, while the second group deals with our responsibilities toward others. But even if you ignored the first group (which I certainly don't advise you to do!), which of the second group would you dismiss? The one forbidding murder, or stealing, or lying, or greed (covetousness), or treating others with respect (especially parents)? No, all those are important, and without them society falls apart.
I omitted one, however, and from what you say elsewhere in your letter I suspect it's your real problem. It's the commandment dealing with sexual purity, and you admit you don't want to follow it. But God knew what He was doing when He included it, because we ignore it at our peril. It gives stability to our lives and our families, and society.
The real issue, however, is this: What place should God have in your life? God made you, and He loves you and knows what is best for you. Jesus' warning is true: "Wide is the gate and broad is the road that leads to destruction" (Matthew 7:13). Don't go down that road, tempting as it is, but commit your life to Christ and build your life on Him.