I got the impression on reading through the posts that whitney has been too available with his ex.
If it were me, I wouldn't. Make her wait--let her think--let her wonder.
Then (later) just a very cool "Thanks". or, if that is uncomfortable for you, make it just "less" than what you normally do. No "Hi" or anything chit-chatty.
She just doesn't get "your best".
I'll be interested in what she does with that!
Have FUN and give that little guy a TON OF KISSES!!