Praise be to Allah.
You should understand that lifespans are already decreed and provision is already allocated; no one will ever die until he has received his provision in full and his time is up. Allah, may He be exalted, is more compassionate to His slave than his own mother; in fact He is more compassionate to him than he is to himself. If Allah were to let the individual decide for himself, and he decreed whatever crossed his mind and what he thinks is best according to his own calculations, thoughts and illusions, none of us would ever be happy in his life and would not manage his own affairs in the manner he hoped for and strove to achieve.
Have you not heard the words of Allah, may He be exalted (interpretation of the meaning): “And in the heaven is your provision, and that which you are promised” [adh-Dhaariyaat 51:22]?
Do you not know that your provision comes only from the Lord of the Worlds, not from your husband? Allah, may He be exalted, says (interpretation of the meaning):
“And no (moving) living creature is there on earth but its provision is due from Allah. And He knows its dwelling place and its deposit (in the uterus, grave, etc.). All is in a Clear Book (Al-Lauh Al-Mahfooz - the Book of Decrees with Allah)”
“And so many a moving (living) creature there is, that carries not its own provision! Allah provides for it and for you. And He is the All-Hearer, the AllKnower”
Have you not heard the hadeeth (Prophetic narration) of ‘Abdullah ibn Mas‘ood (may Allah be pleased with him), who said: The Messenger of Allah (blessings and peace of Allah be upon him), who is the most truthful one, told us: “The creation of any one of you is put together in his mother’s womb for forty days, then he becomes an ‘alaqah (a piece of thick coagulated blood) for a similar period, then he becomes like a chewed piece of flesh (mudghah) for a similar period. Then the angel is sent and he breathes the soul into him and is enjoined to write down four things: his provision, his lifespan, his deeds and whether he is doomed (to Hell) or blessed (destined for Paradise)…”
Narrated by al-Bukhaari, 7454 and Muslim, 2643.
You do not need anything but one thing: you need to think positively of Allah, may He be glorified and exalted, and to put your trust in Him, refer your need to Him, have faith in what is with Him and be content with what He chooses for you.
Allah, may He be exalted, says (interpretation of the meaning):
“And whosoever fears Allaah and keeps his duty to Him, He will make a way for him to get out (from every difficulty).
And He will provide him from (sources) he never could imagine. And whosoever puts his trust in Allaah, then He will suffice him. Verily, Allaah will accomplish his purpose. Indeed Allaah has set a measure for all things”
With regard to your share of your husband’s house, the matter is not as you think.
Yes, if the husband dies and does not have any children, you will have one quarter, but do you know that if he has a son, you will have one eighth and the son will get the rest of the estate? Because the son prevents the brothers and sisters of the deceased, his paternal uncles and all other relatives on the father’s side, apart from the grandfather, from inheriting?
If the child is female, you will get one eighth and the daughter will get half. This means that the child, whatever he or she is, will get a large portion of the house and if it is added to your share, it will become even greater. So why are you worried?
And Allah knows best.