Why could Yosef not restrain himself any longer?
(45,1) “And Yosef could not restrain himself in front of those who were standing around him, and he called out: Remove every man from before me! Thus, no one was with him when Yosef make himself known to his brothers.”
Since Yosef had before now spoken harshly to his brothers many times, why suddenly now could he no longer restrain himself from revealing his identity?
The answer is that we know that the twenty-two years that Yosef was separated from his father Ya’akov corresponded to the twenty-two years that Ya’akov was seprated from his own father, as a measure for measure punishment. And the twenty-two years were calculated very precisely so that they would finish neither one minute earlier or one minute later than the set time.
Therefore when the end of this time period drew near Hashem did not allow Yosef to restrain himself any longer, and he was forced against his will to reveal himself to his brothers in order that there would be exactly enough time for them to go to their father and announce to him at the last moment of the twenty-two years that Yosef was alive.