Conversation so far:
Where was Robert E. Howard born?
Robert E. Howard was born in Peaster, Texas.
Who were Robert E. Howard's parents?
Robert E. Howard's father was Dr. Isaac Mordecai Howard, a traveling country physician and his mother was Hester Jane Ervin Howard.
Did Robert E. Howard have any siblings?
Robert E. Howard was an only son.
How was Robert E Howard's upbringing?
Robert E. Howard, a bookish and intellectual child, often witnessed the effects of injuries and violence in farms and oil fields because his father was a doctor.
Did Robert E. Howard's parents split up?

Question: When did their relationship end?
Self-contained rewrite: When did Robert E. Howard's parent's relationship end?