The theory of paralle universes is also called omniverse, is a hypothetical group of multiple universes including the universe in which we live. Together,these universes comprise everything that exists. If so is true, then the universe consist of multiple parallel realities, each reality represent a possibility. Your present choice is what determin your reality. You can change your destiny by just choosing between the possibilities. I believe destiny is made up of two parts; one that is under your control and a part that’s controlled by God/Universe/karma whatever you call it, the creator of these universes .
Lets take an example, imagine Tom walking down the street and happen to see an ice cream shop. The fact that Tom reached such destination is a blessing from God/ tom’s destiny. However, Tom’s control is to choose whether to take this opportunity or not. Until Tom make up his mind, there exist countless possibilities. Like him buying an ice cream, him not buying an ice, him buying a shake instead, him only using the bathroom or walking away from the ice cream shop…etc. Each of Tom’s possibilities is represented in a future parallel reality. Once Tom make up his mind, he will experience the chosen reality.
What’s crucial to understand is that if Tom have choosen not to eat an ice cream someone else will eat his ice cream. His opportunity will become someone else’s reality, if he didn’t choose it. This applies on everything in life. If you don’t accept the money, the money will go to someone else. If you don’t eat the food, it will get eaten by someone else and so on… This’s the law of life, to every giver there’s a receiver. You have multiple possibilities, but only one opportunity. So it’s either you choose to give and there will be a receiver or you take in place of those who gave away their opportunity. Another way to think about it is to every present there’s the absence of it.