Please tell me if this is weird or not

So I was sitting next to my boyfriend, and he was in his text messages and I noticed his exes friends name there and he cleared their chat ( I know his ex gf because she used to be in my class in hs and ik who her friends are), anyways, I was like wtf, why is he texting his ex girlfriends friend??? so I asked him and hid response was "they're not friends anymore" so I was like and??? why clear the messages, he literally couldn't even answer me, I could physically see him trying to think of something to say and it literally made me feel so uneasy...

I am not really the type to take his phone and go through his shit, but if he is on his phone, sometimes I do look over to see what he is doing and he never minded it , but I literally feel like I wish I never saw that bc I can't stop thinking about it, this happened 2 days ago