help please

okay me and my fiance have been together 11 months. he just recently started working out of town and I went to visit him last weekend and I looked at his phone for something and saw notifications for this dating app. but he has his phone locked and I don't know the passcode so i couldn't look and see what was being said on it. so i created this fake profile to see his profile and i asked him about it and hes saying he used it to connect to old friends bc this certain website used to be used to connect to friends. He told me he deleted the app but i can see he's still active on there. what do I do? we are in two different places now so I domt wanna confront him about it over the phone. please help.