The deputy leader of the Scottish Labour Party announced his resignation after the party discharged an investigation into claims of harassment against him.
Alex Rowley, the MSP for Mid Scotland and Fife, said he was disappointed that the panel was unable to fully investigate the claims so that he could answer them.
He has informed new Scottish leader Richard Leonard of his intentions to give up the role.
In a statement, he said: "I am pleased the panel has discharged the case which I referred to them, but I am disappointed that they were unable fully to investigate - and I to have the opportunity to answer - the allegations, which relate to the acrimonious end to a relationship nearly five years ago.
"This means the only opportunity to do so would have been through the media and I am not prepared to cause that distress to my family.
"I am in politics to fight for social, political and economic change to improve the lives of working people. I will continue that work as a Labour MSP for the region of Mid Scotland and Fife."
Scottish Labour leader Richard Leonard said he had asked Lesley Laird MSP to take on the role in the immediate term.
He added: "I have spoken to Alex and for the sake of his family he has decided to step down from this important role.
"He informs me that it is a decision he made some time ago. He is a loyal and experienced member of the Labour Group in the Scottish Parliament and will continue to play a part in rebuilding the Labour Party in Scotland."