Boyfriend lied??


So November last year my boyfriend told me he was going to block his ex girlfriend because she started being annoying but I went through his phone this morning and he didn’t block her?? And the last message was from last year and she said

Her: “Guess what I got the balls to do? Get my nipples pierced”

Him: “oh?”

Her: “it’s your turn remember you said if I did you would”

Him: “yeah idk about that”

How am I supposed to know he hasn’t deleted messages?? He acted like he didn’t want to talk to her or be friends?? And then I see that??? Why would he even reply 🙄

I’m not sure what to do because if he knows I went through his phone it’ll cause an argument?