Uncomfortable questions

"So neither of you really like the divorce so why did you get it," asks the MC innocently enough when both his father and I are standing there together."
Silence.
I wait to see what his father answers. More silence.
The MC asks again, while swinging on the play set with his brothers and a tootsie pop in his mouth like we could be talking about anything casual.
"If neither of you like the divorce, why did you get it?"
I finally decide to answer with the old line about how it's hard not to understand and how I know he is wishing he had answers, etc.
He pushes his father for an answer who says, something like "we've talked about this before and that's what I've said before," or something dumb.
The MC is understandably unsatisfied and prods again.
I answer this time that "Daddy and I probably have really different perspectives on what happened," and then I excuse myself saying I need to go to the bathroom and change out of my Purim costume. I go in the house and then I hear my STBEX (really it is soon now, hard to believe still not actually just ex, but still "soon to be") tell the boys he's leaving and going to get in his car. Not a surprise.
So much for that conversation. What am I supposed to say. :( I hate not giving my child any answers, because I feel like he learns than that I have no answers when life gives hard questions, but what am I supposed to say with his father standing there. Not that I would have given the real answer had we been alone, but the context was all very uncomfortable.