"Sien"

Vincent’s only live-in girlfriend, 'Sien' committed suicide in 1904 by jumping into a river, just as she had told him she would do (21 years earlier). 

Clasina (Sien) Maria Hoornik

Sien was Van Gogh's only life in lover and partner who he really wanted to wed. Indeed she wanted to marry him also but Vincent's family and benefactors refused to countenance such an arrangement. 
Clasina Hoornik had been one of ten children and when her father died they tried to augment their brother's meagre income selling chairs as cleaners and general labourers, seamstresses and the like. Inevitably for the period 'Sien' became a prostitute and gave birth to four children as a result by the time she was in her early thirties. She had been pregnant when she took up with Vincent and he first began drawing her. There is no doubt Vincent loved her and she him but he contracted gonorrhoea from her and was hospitalised as a result and Theo, Vincent's brother and principal benefactor, was furious and threatened, along with his influence upon his other benefactors, to withdraw their financial support. Their brief relationship and affair de couer came to a tragic end.

Van Gogh, Woman with cigar (Sien) seated near the Stove (April 1882)
Courtesy of Kröller-Müller Museum, Otterlo.