What it means is that every decision that is taken on
earth is already known to the Almighty beforehand, because He is the All-Knowing
God. However, in the case of some such decisions, what is known to Him is
actually expedited through us, as we use our discretionary powers. In other
words, he knows beforehand what we will decide even though His foreknowledge
doesn’t interfere in our free-decision making process. I believe that decisions
on marriages, in most cases, belong to this category.
However, there are other decisions known to the Almighty
which He Himself has taken, for which our discretion is not allowed to play any
role. Our birth, death, parents, and relatives etc., are some of the things on
which we have not been given any discretion. But wherever there’s room to act,
we must act and consciously deal with a situation as best as we can.