Just because you feel that the world was made for the two of you to be together forever doesn’t mean it is true. But it doesn’t mean you shouldn’t live in the moment with that person with the idea of forever. And if the moment of forever falls through, you shouldn’t act like the moments didn’t exist.
Appreciate that your past exists, but do not live in it.
Appreciate that a person who no longer in your life, used to be.
We have people for as long as we need them.
Look forward. Look after yourself.