What should I (25F) do if my fwb (26M) is having sex with other people and didn’t tell me?

I (25F) have a friend (26M) that I have been sleeping with for over 1 year now. Yesterday, as we were in bed, he told me that he has been sleeping with other girls that he is meeting on dating apps and previously one that he works with. We have never had the conversation about being exclusive, so I know that I have no reason to be upset with him. But I can’t help but feel mad that this has been happening for months and he hasn’t told me until now when I have asked him before. I feel like I have a right to know if he is sleeping with other people as sometimes we don’t use a condom. He swears up and down that he always uses them with the other girls and gets tested exc, but it still concerns me. He apologized for not telling me sooner and admitted that he should have. Is it wrong of me to be upset about this? Should I put an end to this “relationship”? It sucks cause he truly is one of my best friends and the sex is good, but I don’t want to get hurt. Even typing this out and reading it back, I sound stupid. But I would appreciate some advice. Thanks everyone