Need some advice.

So I’ve been talking to this guy for about a year now and we finally made it “official” about two weeks ago. Recently I went thru his phone just out of curiosity and found that he sent a message to a girl commenting how pretty she was and sent her the heart eyes emoji “😍😍” on a selfie she put on Snapchat. I asked him about it and he said “he didn’t know why he sent that”. Like come on 🤨. He finally said that he just thought she looked pretty, nothing more. Idk whether to believe him or not. I wasn’t jealous or mad when I saw it, I was more disappointed never thought he was that type of guy. He apologized and everything but I don’t know how to feel about it. It made me feel numb towards him. Made me not trust him. I feel nothing towards him now and it sucks.

Am I overreacting? Should I stop talking to him or should I just forget about it and act like nothing happened.

We were talking about it and these are some of his messages.