Advice needed! My husband 40M got a new work Ipad 37F

Husband 39M and I 37F have been together for close to 10 years. So I may need to be talked off a ledge here for this one. My husband got a new work Ipad that he linked to his phone. He did not bring it with him today and left it in my home office where I am working. I am guessing he did not realize this and the text noise would not stop going off when I was in meetings. I found the thing and went to turn off the notification sound to find the notification of a text being fishy! My husband and I have an open phone policy but we never even look. A text with him and his co-worker was the top notification and it made me feel a little sick! He does talk about her a lot (but she is married so I think nothing of it) and they had a work event together all day yesterday but this seems off. She said “I feel like a terrible person. I felt like I cheated yesterday and told (husbands name)” and sent him a gif of him not caring. My husband said “hahahahah omg” then she went on a rant saying that she bets her husband wishes someone will rake her from him. My husband has not responded. thoughts or advise on how to handle this?