Am I overreacting?

So I went through my boyfriend’s phone last night (I know, I shouldn’t have 😂🙄) but I did and saw DMs between him and his ex. He was saying how he loved her, how he’s always gonna be there for her, she “knows what it is” between them, asked for her number and said he was gonna come see her THREE WEEKS AGO. So I calmly put my clothes on and walk to my car 😌 I look up and he’s running up to my car and opened the door asking why I was leaving.. I told him what I saw and he said that he only said that because someone that’s close to her died and he was being supportive 🙄 I don’t wanna be with him anymore and he’s acting like he has no idea why I feel this way. Am I overreacting?