The term that could be best described as the way that Kevin is thinking is a social comparison. Social comparison is being defined as a way of individual's determine his or her social worth in which could be based from how the person stack against other people in which we could see how Kevin felt better after finding out that Samantha was struggling more than him.
God promised to make Abraham the father of a great people and said that Abraham and his descendants must obey God. In return God would guide them and protect them and give them the land of Israel.
It is better for a child to be raised by parents who go there separate ways and presumably have less day to day conflicts
