She praises qualities the other man has. She notices differences she never cared about before. She does not plan to measure the two men against each other. Yet attraction highlights unmet needs. The mind starts asking silent questions.
She protects her privacy more than usual
Her phone is always close. Notifications get turned face down. She changes the subject when someone asks about her day. It is not necessarily a sign of wrongdoing. It is a way to avoid judgment. And to keep a new emotional world untouched.
Guilt appears long before any line is crossed
She wonders why she feels so much. Why she looks forward to seeing him. Why her heart races for someone who is not her husband. She may feel ashamed. She may try to bury the thought. But guilt means she knows what is at stake.