Quoting Viv, Ev & Gwen ♥:" I think that answer is fine for now. He's still very young."
I agree, deeper explanation of the subject of "where's daddy" will definately need to happen when LO is old enough to persist in questioning, as they will definitely do as they get older. At that time it is best to be as truthful as you can, but be careful not to badmouth their father in front of them, as that can create feelings of "it's my fault" and resentment towards you. My mother had to go through this with my brother, I was only 6 months and thus not bothered, and she was far from gentle in her description of our father. She still hates him to this day, but my brother did not respond well to her explanations of "Daddy is a jerk and doesn't want to see you" So, yeah, she was a frazzled single mom with no help from our father, so we don't blame her now that we're grown, but it did make for some very difficult times in our teen years especially.
As if teens didn't give their parents enough problems.