 As she grew older Betsy suffered from numerous illnesses , the exact natures of which are not recorded but which are known to have caused William great concern . William began to become paranoid that Betsy would marry and leave his service , in 1835 going as far as to have her sign an affidavit that she would never leave him . In 1843 his older brother Charles , a successful planter in Java , returned to England after over 30 years abroad . William became deeply suspicious that Betsy was becoming too close to Charles , a suspicion intensified when Charles took her on a visit to Holland and the Rhine ; Charles returned to Java in 1845 . In around 1844 Betsy struck up a close relationship with the pen manufacturer and art collector Joseph Gillott , one of William 's regular customers who owned some of his pictures . Gillott was married with children , and the closeness of their relationship caused William concern . In 1848 , William retired to York leaving Betsy alone in his London apartment ; although aware that Betsy was considering marriage he was confident that he could persuade her to come to York and live with him in his retirement . Betsy did eventually join him in York , and was present at his death . 
