Predestination, in theology, is the doctrine that all events have been willed by God, usually with reference to the eventual fate of the individual soul. Explanations of predestination often seek to address the "paradox of free will", whereby God's omniscience seems incompatible with human free will. In this usage, predestination can be regarded as a form of religious determinism; and usually predeterminism.
The general understanding of this verse is that things are generally created in pairs (for instance, positive and negative, matter and antimatter, light and dark, or male and female), and that one of the signs of Allah is that human beings marry and form a pair in order to become more whole than they would be individually.
However, it is not usually taken to mean that all human beings are specifically created with a soulmate or "pair" whom they marry in this world. Indeed, some people have more than one happy marriage in their lifetimes; others are miserable in their marriages!
Marriage can be destined and can be a matter of free choice; matters of destiny are not usually clear. Some people misuse the idea of destiny and marriage to cover up socially unjust practices (for instance, not allowing their children to marry someone of a certain race, culture, family, or profession) and then saying these restrictions are "destiny". At the same time, it does seem that sometimes some people are destined to be together or destined not to be together.
However if you are happy with your husband, I hope you will be able to be together in the Hereafter!
Our existence itself is a great bounty from Allah who created us, out of His Mercy and Grace on us. He created us after we were nothing ( Has here not been over man a time, when he was not a thing worth mentioning?) (Sura 76, Verse 1).
He provided us not only with life but also with all what require to live a decent life e.g. He gifted us with the intellect and reason and ability to listen, see, and distinguish good from bad. He gifted us will all sense which make us enjoy our life and be away from danger. He showed us the best way to live our life with harmony and peace between ourselves and our desires and wishes, and between ourselves and our Creator, and between ourselves and the Universe.
What ever bounty we have is from Him, and what ever suffering we may have is from ourselves.(Whatever good reaches you is from Allah, and whatever bad comes to ou is from yourself). (Sura 4, Verse 79).
He guided us to live in the best way away from evil and sinful desires. Those who follow the way of Allah (SWT) enjoy life in the best way as that achieve the Peace of Mind and Tranquility which is lost in he life of millions who are away from Allah.
We are unable to thank Him enough but when we try to thank Allah for His countless bounties, we feel the taste of life and feel more peace in our hearts.
Allah guides every one who wants to be guided, and when Allah guides some one, no one will be able to misguide him.
Those who reject and insist on rejecting the truth, will leave them to themselves with out guidance from Allah, because they insisted on rejecting. This is the meaning of misguiding. Allah does not misguide any one, but leaves the tyrant sinners with out guiding as they have insisted on rejecting His guidance, and that situation of leaving them to themselves is called misguiding. It means leaving them to what they wanted , with out guidance of Allah.
Such tyrant sinners will never be guided unless they change their minds and selves.
When Allah says that He will guide whom He wills, it reminds us to be humble. We cannot consciously choose guidance in the same way that we might go to a shop and buy bread. Nor do we deserve it automatically.
Rather, guidance - like faith, wisdom, and other intangibles - is a gift bestowed upon us by the divine, and is something we should be grateful for, rather than arrogantly thinking that we determined it on our own.
However, these intangibles - like guidance, faith, and wisdom - are not bestowed on people randomly. They are similar to plants growing from a seed. A person can prepare the ground, plant the seed, water the plant, and so on, but after they have done everything they can, all they can do is pray that the plant will grow well. However, that person will have a much better chance of the plant growing than someone who simply throws a seed on the ground in the desert and ignores it.
Similarly, we can prepare the ground of our hearts to receive guidance, etc, by sincerely seeking the truth; acting honestly, genuinely, and humbly; putting forth eforts to seek knowledge, and the like. Thus we "earn" guidance - but, of course, we are reminded that we cannot force it through our actions.
Conversely, some people disqualify themselves from guidance by indulging in evil, destroying their souls, being arrogant, or doing other things which seal their hearts. They would not benefit from the guidance even if a tablet descended to them from the heavens because they are not ready to receive it.
Allah is just, merciful, and all-knowing and would not deprive someone of guidance unjustly.
It is an excellent question to ponder however!
You can find more discussions of this question in the tafsir of the relevant ayat.
Prophets were selected by Allah The Glorious, according to His Absolute Knowledge about every thing including the future of every creature. He knows who will be among all humans the most humble and who will not commit sins and who will be suitable to guide people. All Prophets were ordinary persons but Allah selected them because of the top piousness from all people to guide people. (Aal Imran: 33).