because of the trinity he is god man god spirit and god father simeltanously
When I tried to post this, I was told by the computer that twenty-four new replies were posted since I started typing. LOL. Anyway, I spent a bit of time trying to make sure I wasn't being heretical, so I'm going to post this anyway.
The Trinity is three Persons: Father, Son, and Holy Spirit.
One of these Persons, the Son, became man. The Father and the Holy Spirit did not become man, only the Son. Without "leaving" where he always was, the Son entered into creation in a way he had not before, as one of us. We know him as Jesus.
Being divine, he is incapable of dying, but having become man, he has taken upon himself "body, mind, and soul, and everything that is in man, truly and not in semblance" (cf. liturgical creed, Armenian Apostolic Church), without ceasing to be divine as he always was. He was incapable of dying before he became man, but afterwards not only could he die, but he did die. In this sense, we can say that "God died on the Cross", but it is only in this sense. The Father and the Holy Spirit did not die on the Cross, the Trinity did not die on the Cross.