It sounds to me like he's simply playing male pouty "tit-for-tat" since you went there on YOUR birthday.
I would suggest doing something SIMPLE on Thursday nite -- nothing elaborate or romantic. A nice card and gift from son(s), and a Shoebox-type card from you and a practical-ish gift. Nothing over-the-top or romantic.
On his actual birthday, a simple "Happy Birthday! Hope you have a good day" text maybe.
