does this count as cheating

My boyfriend got nudes from another girl and didn't tell me about it just deleted their conversation. It wasn't the first time she messaged him from what I know she's been messaging him for over a month. I found out because he sent the pics to his friend to laugh about it. He says it wasn't sexual he just thought it was funny and he didn't cheat on me. I say it was cheating because he kept it from me and didn't delete her afterwards.