"自分のキャリアを悪い彼氏のように扱いなさい"

Simplified Meaning:

Think of your job or career like it's an unreliable boyfriend. Imagine if you had a boyfriend who was not dependable, made you anxious, or didn't always treat you well. You wouldn't rely on this boyfriend for your happiness or well-being, right? Instead, you would focus on your own goals, interests, and making sure you're satisfied with your life outside of this relationship. In the same way, don't let your job control your happiness or sense of worth. Have other interests and hobbies that you enjoy, and don't rely entirely on your job for your sense of identity. If your work situation isn't ideal, remember that you can always move on to something better. Protect your well-being and focus on what makes you feel fulfilled and happy outside of work. This way, your career won't have the power to completely ruin your mood or self-esteem.