The existence of God Almighty (Allah) is not the same as a creature's existence. The human's existence is dependent on God's decision to keep this creature existing on, therefore the existence of a human or another creature is not absolute.
The name Qayyum (القيوم) means, the One who is always existing and who keeps others existing. It is one of the Names of God in Islam. It means, my existence or your existence is dependent on God's keeping it standing. This is why I called it in the title 'relative existence'.
We, creatures (including Jesus as a humble creature), we exist only as long as God wants us to exist. This is why our existence is relative. As if an electricity turned on and off a million times in a second.