Certain verses from the Quran and religious texts indicate that when a person sins and afterwards repents and regrets what he has done and decides to stop committing such a sin, then almighty Allah will not punish him.
The belief of "Qadha" and "Qadar" (fatalism and destiny) in the teachings of the Ahlulbait (peace be upon them) is "al-Amr baynal-Amrain" - a path between absolute fatalism and absolute freedom. This means that the human being is capable of the actions, has a choice in doing them and is responsible for their consequences; but at the same time, he is under the power of Almighty Allah, since the abilities of the human being is not independent from His power. The human capability is limited by the creation of Almighty Allah and His continuous maintaining of the life of the human being.
If the mentioned condition was part of the marriage contract, the divorce is not valid, and the woman is still his wife, based on the mentioned details.
The Shirk belief that takes the person outside Islam is believing in a partner to the Almighty Creator in His creation, like believing in a god for goodness and another for evil etc. Another form of it is worshiping idols as Arabs used to do in the time of ignorance before Islam. Lesser Shirk is, for example, showing off in one’s acts of worship. This is a major sin, but does not take a person outside the fold of Islam.