What are the conditions for a man to marry a second time in Islam, and what is the evidence for this from the Qur'an and Sunnah?

For the permissibility of polygyny, it is a condition that a man must be sure he will not be unjust, according to the Almighty’s saying: {But if you fear that you will not be just, then [marry only] one}. As for the condition of being able to afford the expenses of marriage, there is a difference of opinion among scholars regarding it.