Is it necessary to explain the reasons for leaving a relationship or marriage, even if the other person asks for an explanation?

What should I do? My boyfriend constantly yells at me because I’m very forgetful. I have been like this since I was a little kid. I used to fail my classes because of my memory.
It just pains me to see me losing with people and people can easily read my mind. What can I do?
Do you agree with the special legislative committee that a sheriff should show and uphold "the highest standards of honesty, integrity, conduct, and service"?