What should I️ do?

My husbands birthday is coming up and I️ sneaked through his phone and got a few of his close friends numbers. One being a girl named Vanessa. I️ texted her today and it wasn’t her. I️ remembered that she’s under V-Dog after this other girl responded. I️ do know my husband still has numbers from women he used to date, dated or just talked to. Because he doenst delete shit. Should I️ ask him who it is or just let it go? The woman responded and said Justin who? Cause she knew a few. This is obviously someone he used to talk to but doesn’t anymore