Not necessary, by his choice. The freedom to accept a death he could have spared himself is what makes it pure love.
Oh I do agree on that:
17“The Father loves me because I sacrifice my life so I may take it back again. 18No one can take my life from me. I sacrifice it voluntarily. For I have the authority to lay it down when I want to and also to take it up again. For this is what my Father has commanded.”