Should I be worried?

So me and my boyfriend broke up for a little time while. We cleared everything on social media for anyone to even know that we had dated. But we got back together after a while and he won't tell anyone that were dating again. I've told my friends and even have it known were dating again on social media. I had to talk to him just let it be known he's taken on socail media. But it's not known he is dating me. Sadly, I went through his phone just to see if he was cheating 🙈 (I know that's awful) but this one girl had stuck out to me... she was flirting with him and he some what turned them down but I don't think she knew he was taken. She asked to hang out with him this weekend and he said that he was going out with friends. But with us dating, we had just went back to the normal date of us dating. So this weekend is our anniversary. I asked him if we could hang out this weekend and used the same excuse that he used with the other girl. I don't know what to do about it or if I should be worried... 🙄🙈