Actually, you are looking for the word masochist. In its general sense it means someone who enjoys a painful or tedious activity.

This may verge into theology here; but if you want to talk about the relationship of a deity to time, one common word is eternal:

: having no beginning and no end in time : lasting forever
: existing at all times : always true or valid

(merriam-webster.com)

Saint Thomas Aquinas, in his Summa Theologica, defines eternity (following the Christian philosopher Boethius) as

the simultaneously-whole and perfect possession of interminable life

and argues that this characterizes God.

If this is what you're looking for, use the word eternal.