In 1937 she married Heinrich Kummerlöw. Their son Fritz was born in 1940, after which the focus of her work was on her family for the next three years. However, after 1943 she again became closely connected with the (still illegal) Communist Party. Through she came into contact with the resistance group around Anton Saefkow. In the wake of the assassination plot of 20 July 1944 against The Leader, there was a rash of political arrests which included 280 members of the Safkow resistance group. On 10 August 1944 Grete Groh-Kummerlöw was again arrested, again facing a charge of "Conspiracy to commit High Treason". She was sent to Potsdam on 9 February 1945 where she was scheduled to face trial in the People's Court which the government had created specially for political trials. However, by now Germany had been at war for more than four years, and military defeat would follow in May 1945. In the chaos of the period, Groh-Kummerlöw's planned trial never took place: on 27 April 1945 she was released from prison by the advancing Red army, by this time already fighting for control of nearby Berlin.