When you're dating someone who is already in a relationship, it's a horrible idea, especially when there are so many people involved, and in the end, someone is always harmed, typically in more ways than one. You may have heard that you should go for your dreams and not let anything stand in your way. That's true to an extent but sometimes you need to make compromises in order to live your life. If you really want to hurt someone or cause them pain, you should never date anyone else while they are still in a relationship with someone else. It's called cheating, and it can destroy any kind of love you might have had together. Even if they treat their partner badly or force them to break up, at least they won't be able to say that they weren't given a chance to change. Of course, not all relationships work out as expected. Sometimes one person in the relationship decides they no longer want to be with each other even though they both thought they were in this thing forever. In these cases, it's best to move on from the situation before things get too far along. There's no use in hurting someone because you didn't get what you wanted in the end. Dating multiple people at once is not only unwise but also extremely dangerous. If you do this then you will be putting yourself in a lot of stressful situations that you can't control.