Have you ever loved someone and knew, deep down, that they were not a healthy choice for your life?
Maybe your little internal voice was telling you to end it, but you stayed with the person anyway. You probably hoped that your instinctual little voice was just being overbearing.
Or maybe you were hoping against all hope that the warning signs were false alarms and that the concerning issues would be brief and temporary.
When your best friend is dating a dud, it is as plain as day what the right course of action should be.