Alhamdulillah, wassalatu wassalam ala Rasulillah.

The most common doubt that occurs during a marital crisis is, "Has my destiny been tied up?" (through black magic and witchcraft, etc). First, let us see what Islam has to say about it. Allah declares in the Qur'an: If Allah puts you into any hardship, the entire universe cannot remove it. If Allah decides to bless you, then nobody can stop Him from doing so.

So, nobody is responsible for anyone's delay in marriage, financial supplies or birth of offsprings. People have just invented such threats claiming to control people's destiny, whereas Allah announces: If Allah opens the door of His Mercy (prosperity, marriage, happiness) for any one, nobody can stop him from receiving it.  

The entire life of the Prophet (blessings and peace of Allah be upon him), passed away in refuting such allegations of being possessed or bewitched. All his sons died in infancy, yet we dont say it was due to witchcraft. There were so many Prophets who never had children, because Allah did not bestow on them. That is why, in order to keep the ummah away from such thoughts that a person's destiny can be tied up, the Prophet, (blessings and peace of Allah be upon him), in one of his famous narrations, gave fifteen important advice to his cousin, Ibn Abbas r.a.a. One of them was, "O Slave of Allah! If the entire humanity and Jinns come together to give you some benefit, they cannot do except what is destined by Allah. If the entire humanity and Jinns come together to harm you, they cannot cause you any harm, except what is destined by Allah". 

The Prophet, (blessings and peace of Allah be upon him), declared that a person cannot be a believer until he does not accept with his heart that whatever he has got is because of his destiny, and whatever he did not get is also because it was not written in his destiny. 

Therefore, I have presented the evidence from the Qur'an and Sunnah, that believing in harming or benefitting destiny is an act of shirk. Nobody can stop Allah. So, in order to make your belief firm in Allah, the Prophet, (blessings and peace of Allah be upon him), assures that when you pray five times, recite after each salah: Allahumma la mani'a lima a'tayta, wa la mu'tiya lima mana'ta, wa la yanfa'u dhal-jaddi, minkal-jaddu. (O Allah! None can deny that which You bestow and none can bestow that which You hold back; and the greatness of the great will be of no avail to them against You). 

If you are not getting married then make Dua to Allah and do a lot of Istaghfar. One such Dua is from Surah Furqan : Rabbana hab lana min azwaajina wa dhurriyyaatina qurrata a'yunin waj'alna lil- muttaqeena imaama (Our Lord! Bestow on us from our wives and our offspring who will be the comfort of our eyes, and make us leaders for the Muttaqoon (the pious)).

When Ibrahim a.s. walked out of the fire being saved by Allah, he left his native place and travelled alone, praying, "Rabbi Habli minassaliheen (O Allah! grant me Saliheen (wives and children). 

You must also make Dua that are from the Sunnah of the Prophet, (blessings and peace of Allah be upon him). Whenever he faced any hardship, he used to say, "Allahumma la sahla illa ma ja'altu sahla, wa 'anta taj-alul hazna idha shi'ta sahla" (O Allah! There is nothing easy except what You make easy, and You make the difficult easy if it be Your Will).

It is narrated in the authentic Hadith that whenever any hardship appeared impossible to be solved, the Prophet, (blessings and peace of Allah be upon him), used to recite this Dua and teach others too to recite it: Allahumma la sahla illa ma ja'altu sahla, wa 'anta taj-alul hazna idha shi'ta sahla

The prophet, (blessings and peace of Allah be upon him), called upon his beloved daughter Fatima and said, "O Fatima, you are my daughter. Let me teach you a Dua which you should never leave out: “Allahumma rahmataka arju fa la takilni ila nafsi tarfata ‘aynin wa aslih li shani kullahu, la ilaha illa anta (O Allah, for Your mercy I hope, so do not abandon me to myself even for a moment. And correct all my affairs. There is no god but You).”

In this supplication, the mercy of Allah is beseeched by the supplicator, and we note that there is no amulet or any other thing given to his daughter Fatima r.a.a. So, this is what you need to do and finally know that 'walikulli ajali musamma' (for every decision (of Allah) there is a fixed time). Nothing can happen before his will.

But at times, due to or own high expectations, we fail to get a good proposal. Our parameters are raised so high that nobody can fit into it. That is why Deen should be on priority, because Nikah protects Deen as well. Don't be too fussy about choices that can cause lots of rejections either from your parents or you. May Allah grant you a good spouse. Ameen!

And Allaah knows best.