Do not underestimate the power of observation to understand your partner
Your partner may not be entirely comfortable telling you what makes her anxious. For them, the disorder is deeply personal and at certain times, they feel embarrassed about it. Observe and watch closely what makes him/her anxious and try to determine what makes them comfortable or not. Even in instances where your partner might tell you, certain triggers might not be mentioned, and it is your concern to find out.
