How can I find out more about the 12 disciples and their lives and families than is mentioned in the Scriptures?
What did they give up and who they left behind, in order to follow Christ.
The Bible tells us everything we need to know about the 12 disciples who were initially appointed by Jesus to follow him. Their experiences are described in the four Gospels and additional insights are to be found in the Acts of the Apostles. However, for more information, try this:
Twelve Ordinary Men by John MacArthur published by Christian Book.com https://www.christianbook.com/Christian/Books/product?event=AFF&p=1011693&item_no=88244
There were more than 12 disciples and the article in this link discusses the 70 (or 72) that Jesus sent out: https://www.gotquestions.org/70-or-72-disciples.html
Since God did not consider it important for us to know the names of the 70 (or 72) disciples He charged with the important task of preparing the way for Jesus, we don’t need to consider it important, either. What Jesus called attention to was not the power He gave them but the fact that their names were written in heaven (Luke 10:20).
I found some other articles on the 12 disciples, which I hope will help you:
Edit: Here is some information on Peter, taken from the Bible:
Simon was originally from Bethsaida (John 1:44) and lived in Capernaum (Mark 1:29), both cities on the coast of the Sea of Galilee. He was married (1 Corinthians 9:5), and he and James and John were partners in a profitable fishing business (Luke 5:10). Simon met Jesus through his brother Andrew, who had followed Jesus after hearing John the Baptist proclaim that Jesus was the Lamb of God (John 1:35-36). Andrew immediately went to find his brother to bring him to Jesus. Upon meeting Simon, Jesus gave him a new name: Cephas (Aramaic) or Peter (Greek), which means “rock” (John 1:40-42). Later, Jesus officially called Peter to follow Him, producing a miraculous catch of fish (Luke 5:1-7). Immediately, Peter left everything behind to follow the Lord (verse 11). Source: https://www.gotquestions.org/life-Peter.html