What must I do now, given that I used to commit acts that nullify ablution during ghusl unknowingly, and I used to pray in clothes stained with effect of prostatic fluid (wady) unknowingly?

If one does not re-wash the parts of the body used for ablution after an invalidating act occurs, then they must make up the prayers they performed with an invalidated ablution, because it is a debt upon them. The Prophet, peace be upon him, said: "Allah's debt is more worthy of being paid."

However, Shaykh al-Islam Ibn Taymiyyah and those who agreed with him were of the view that whoever did so out of ignorance of the ruling is not required to repeat past prayers. Rather, they should repeat the current prayer and adhere to it in the future. They supported this by citing that the Prophet, peace be upon him, did not order Umar and Ammar to repeat their prayers when they were in a state of major impurity and Umar did not pray, while Ammar prayed by rolling in the dust. He also did not order Abu Dharr to repeat his prayers when he was in a state of major impurity and remained for days without praying. They also cited the story of the Bedouin who prayed incorrectly, where the Prophet, peace be upon him, ordered him to repeat the current prayer but did not order him to repeat past ones.

As for ritual impurity (khabath), if one prays with impurity, being ignorant of it or its presence, their prayer is valid and they are not required to repeat it. This is the stronger opinion. Ibn Uthaymeen said: "There is no repetition upon him, whether he forgot it, or forgot to wash it, or was ignorant that it afflicted him, or was ignorant that it was among the impurities, or was ignorant of its ruling, or was ignorant that it was before the prayer, or after the prayer."