It was caused by Marek himself when, instead of helping the panicked actor, instead of fulfilling his innocent wish, Marczak raised his hand on him. When Dominik, full of love towards him, decided to forgive him, he committed another dirty trick, thus shattering the last chance to return to each other.
He didn't know then that he had really lost him, and he didn't understand that he had hurt the man he really loves.
The awareness of both the harm done and the emptiness after Dominik's departure came to Marek later, too late for anything to be done about it.
Dominik found happiness with another man.
