this could be a son of hers https://en.wikipedia.org/wiki/Marko_Djurdjevi%C4%87 In 1976, after moving to Amsterdam, Abramović met the West German performance artist Uwe Laysiepen, who went by the single name Ulay. They began living and performing together that year.  https://en.wikipedia.org/wiki/Marina_Abramovi%C4%87 there was a gap in her performances with Ulay in "79"