Am I wrong to feel hurt by my boyfriend calling other girls dear and hiding our relationship?

Hi everyone, I really need an objective perspective on my situation. Both my boyfriend and I hold conservative/religious values. Since our relationship started, I stopped talking to guys I used to practice English with on HelloTalk, and whenever a guy texts me, I immediately delete it. My boyfriend talks to women for work, which I completely understand. However, the recent events have really exhausted me:
A girl he used to practice languages with on HelloTalk recently texted him "Hi, how are you?". He showed it to me, but he didn't delete the message. What hurts the most is that he admitted he feels embarrassed to tell girls in his circle or on these apps that he has friends! This girl doesn't even know I exist.

Looking back at their past chat history, I saw they were texting at 1:00 AM. He was calling her dear and saying things like "We should talk to each other sometimes, it helps a person relax." When I practiced languages in the past, I kept it strictly professional, in English, and always made it clear to everyone that I had a boyfriend. He, on the other hand, was chatting in Turkish late at night, calling her "dear" and sharing personal feelings.

I noticed he deleted messages from group chats containing girls on Telegram and WhatsApp. When I asked why he deleted them, he tried to pin it on me, saying: "You once asked why I kept so many messages when you looked at my phone, so I cleaned them up because you wanted me to." But because I trusted him at the time, I hadn't actually read those group messages line by line.

To defend himself, he says, "You were talking on HelloTalk at the beginning of our relationship too." Except I was strictly practicing English professionally and telling everyone I was taken, whereas he was having intimate late-night conversations in his native languag
Am I wrong to feel hurt by my boyfriend calling other girls dear and hiding our relationship?
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