Advice on Parenting Situation

Should I be expected to share every single gift I give to our kids?

Ok, so…I gave my 13-year old son my old Apple Watch that can be used with his cell phone versus just tossing it into a junk drawer never to see daylight again. Well, today I get a text from his stepmom that I should have mentioned it to her (not even to dad) that I gave him the watch. It literally is a WATCH and a gift from me to my son. In no way did this affect them and I didn’t think it was a big deal since the screen time on his phone (which they know about) also affects his watch. However, she’s making it out to be a big deal and saying that I’m playing “favorites” between my kids…over….a….watch…My other kids are wayyy too young for a phone and have no use for an Apple Watch considering they don’t even have phones. They weren’t even upset when they were with me, but she’s claiming they are now and saying it was wrong of me not to mention the gift before giving it to my son. I don’t ask my kids’ dad to tell me about any gifts they give to our kids even when I may not agree….Am I missing something?

Let me add: I’m the Custodial Parent and Primary Residence for my kids. This happens A LOT and I just needed to vent.