Am I overreacting?

My husband has a 6 year old daughter, from a fling he had while in his 20s.. she's my best friend & I love her to death, but her mom texts my husband, sometimes 10x a day (honestly) pictures of her, or some new thing she learned. I'm totally fine with them texting that stuff don't get me wrong.. but isn't that a little excessive? Sometimes if he doesn't respond, she'll (the mom) will ask why he doesn't give a shit about his daughter (eye roll he obviously does) Is it wrong of me to be annoyed with this? He doesn't say anything but I get sick of his phone going off every 2 min with another txt from her. She's married now with another child.. she's always texting his mom & sister too