To expand on your perception is to realize how limited your basic senses are; eyes, ears, touch, smell, taste. These senses add depth to your perceived world. What we see is interpreted by our minds and shapes reality according to our beliefs. You may have heard people see what they wish to see or, justify what they choose.
Yet, what about things that are invisible? In this existence, people will experience connectedness, mystery, and immeasurable points of view that defy description. If we pay attention to both the perceived and invisible worlds, our beliefs will create a more complete picture. We will grasp we're a part of everything. This can help you see beyond your ego, that may periodically control you.
On top of that, do you realize your values change along with your perception? They both change as your desires evolve, and the life you envision emerges. If you desire or covet things that appear to belong to other people, and you focus enough energy and will in this direction, you may justify what future you imagine and why you act to take it away from others. As you reflect on your life honestly, you may have done this before. It may have been the case of someone else's girlfriend, toy, candy, dessert, opportunity or another source of perceived happiness. What does your jealousy, rivalry and desire to steal that away tell you about yourself?
The concept of what is “wrong” may defy human senses. The word refers to where a person is “mistaken” or when a person is “immoral.” An action is mistaken (doesn't work) if you don't get your desired result. Whether an action can be described as ‘immoral’ is trickier, because social codes and laws vary widely, and what you think is 'right' or 'okay' changes based on you. You may say, "that person doesn't deserve to be happy as much as I do," or, "that girl is not good enough for him, and I'm better," or, "that person has more than enough, I'll take some for me," or, "I'm entitled to do whatever I want." You may have a selective (or absent) conscience.
What is all this implying? Perhaps its time you shake yourself senseless in order to determine your reasons for behavior that should make you feel uncomfortable. Why would you feel it necessary to take away from others what you don't have? What you've done is past. Yet, you can grow to better understand why you have been hurtful, unethical, insensitive, self-centered, under-handed or immoral. You have opportunitites to make amends with yourself and others, to learn lessons and plan differently in similar circumstances next time. It's never to late to change, or forgive. Jealousy has many causes. It tends to grow if left untamed. As you identify causes, controlling it will get easier. No one can change your life except for you.