AIO to my husband (we’re both 45) being friends with a 31 year old woman that he works with who he also texts often (messages are between him and her)

I don’t consider myself a jealous or insecure person up until this point in my life and I’m really trying to see past that and look at it in a neutral way because I may be overreacting to the situation.

At first I didn’t think much of it because she is also friends with his best friend and other people they hang around from work. The past few months they seem to have become weirdly close. Well tonight I decided to just look at his phone and they talk way more than I ever thought they did. Nothing seems incriminating but is this normal? I got pretty upset after and he said “she’s just a kid. Why are you getting upset?” and acted like I was being paranoid.

Like I said I could have found much worse but I think this constant daily texting is weird. I’m trying to tell myself I’m just overreacting because I think she is one of the prettiest people I’ve probably ever seen in person and am projecting my insecurities on her. Please let me know if I’m overreacting.