Search Results: sure signs a girl likes you

Me and my boyfriend have been dating for since late July. He treats me like a princess, introduced me to his family, and I see him everyday. We have such a close relationship and he tells me everything (he texts in front of me, doesn't hide his phone, and when a girls tries to hit on him we laugh about it together.) He is a really good looking guy which makes me feel insecure, and many girls throw themselves at him.
Our first kiss happened two weeks after dating, and things are heating up slowly. I like that about him. I think he knows I'm a virgin since I get really shy when we kiss. However yesterday night he forgot his phone at my house, and my curiosity (I know its WRONG!), got the best of me. So yes I snooped through his DM's.
He had MANY girls in his DMs but ignored them, and the rest he was very cold.
I kept scrolling down to the only red flag. On August 6, when he was on vacation in Cyprus with his teammates. At that time we would facetime everyday and talk for hours. However I found this message (yes we were in a relationship back then but very early stage), and this girl was sexting him. He turned her down a couple of times, but in one message she said she wanted to see his dick and he said she will. The next day he texted her saying he was coming over, but she told him she wasn't home at the time. He said nothing happened with girls while he was away (which is technically true) and he didn't want anything to happen. But HE invited himself over to that girl's house. She tried to see him again a few days after, but he rejected her saying he was busy with mates. (he told me he rejected this girl who invited him over but never told me that he invited himself over as well a day before...).
I'm not sure if I should hold him accountable and stop trusting him, or if this is a sign of a potential future cheater.
I can't even talk to him about it because i snooped through his privacy!