Immediate help

So, today is the dating anniversary of me and my husband... but i also seen he’s been texting a coworker and it’s mostly innocent BUT she’s muted so that he doesn’t get notifications when she text.. they usually talk about work but today she says she had to change her number bc of people like MY HUSBAND texting her (she’s in a relationship). He says something along the lines like he understands bc i went through his phone before... I’m so torn. My best friend says don’t say anything until i have enough evidence.. she doesn’t live so i know they’re not seeing each BUT he told her he was upset she didn’t apply to a position closer... idk what to do.. help