Should you forgive cheating or file for divorce right away? It’s not easy to answer when you’ve been together for years, but one woman discovered the truth in an unexpected way.

She found out her husband was cheating when he came home with a brand-new iPhone, claiming it was a gift from his colleagues. Suspicious, she checked his old phone and called a contact labeled “Jack, tire master.” To her shock, a woman answered the mobile number, while the landline turned out to be connected to an expensive shoe store. Digging deeper, she found an Instagram account of a girl who’d been getting gifts from her husband—including a vacation photo with him.

Her discovery led to the revelation that he’d been spending his new promotion money on his mistress. When she confronted him, he begged for forgiveness, but it was too late. She filed for divorce. Her takeaway: “Never underestimate a woman’s logic.”