Couldn't you get a little card tomorrow and sign it from your ex, just to make your son feel a tad better? That's what I'd do, who cares about a little white lie now and then if it takes away his pain. Poor little mite, he must feel really hurt, especially as it happened last year too! Maybe in hindsight you should have expected this and got that card ready anyways?

that's so unfair, he is an a*%$£"e. Hope your son had a nice birthday anyway

I was going to say what Helena suggested get him a little card and just pretend i know its not right but to a little child whats the harm...