Texting woman from work

Question

My husband is the only male working in an elementary school building as an administrator. One teacher there he has started talking to more, or maybe I just noticed. She’s slightly younger than we are, has a young daughter and is married. She however keeps texting him. Like on his personal phone instead of his work phone. She texts him pictures of things she’s doing, and whatnot. I had our third baby in June and she came over (stayed outside) and brought diapers and wipes- my husband didn’t tell me until last minute she was on her way, he said he didn’t know. She also invited us to swim at her MIL pool once but the baby had his one month dr visit so my husband just took our two girls.

Recently I noticed she’s texting him info about her other job, workout stats, and pictures of her video game screen while supposed to be in a zoom meeting for work. My husband responds and has mentioned me and her husband too- so it’s not like he’s not talking about us I guess but to me it’s so weird. I can’t imagine just texting some dude from work. Am I being silly?

I am also a teacher and also couldn’t imagine texting my administrator this personally and she’s a woman. I should mention he’s not the head administrator and he doesn’t evaluate her

Deleted pictures of texts