Why did poe wrote his letter of march 19 1827 to john allan?

Edgar Allan Poe wrote a letter to John Allan on the 19th March 1827 to let him know that he was going to leave the latter's house in order to find a place where he could be treated in a better way. He had heard Mr. Allan saying he had no affection for him, so he thought it over for days, and finally reached to the conclusion that that house, was not a good place for him to leave.