If you have insufficient interest in dedicating yourself to God, you don't have to be separated from the world either. And if you aren't anxious to be on God's side after that final separation, then you don't have to be on God's side now either. It really is that simple and that true. When you begin to see and value separation from that perspective, then you see that separation is your gift of love to God. Separation from the heart does not come because of church rules and discipline, nor does it result merely from the expectations and enforcement of your parents, nor does it happen as a necessary by-product of positive peer pressure.
Genuine separation is the fruit of a very special relationship.
Without the relationship you don't have the fruit. Without the relationship you don't have to be separate. Separation is required exclusively of those who have God as their Father and Jesus as their Lord and Savior. If so, you will desire and strive to be separate from anything that is not worthy of His child. If you have that relationship, you will reject anything that thwarts His lordship in your life.