Gently and soon. I do understand what you were trying to do. I do applaud you for taking some risks. But this man deserves to have someone in his life who loves him wholeheartedly, not someone who is in the relationship primarily to struggle with her own issues. Follow your good instincts. Thank him for his love and attention. Tell him some of what you have told me to make it clear to him that it isn’t about him but rather that it is about your own unresolved problems. Let him know that you wish it were different and that he is a fine and good person in your eyes. Free him to find someone who can reciprocate his love.
Then get some therapy. Your impulse to make change is a good one! Anxiety is treatable. There are better ways to handle it than living this double life. Furthermore, there are reasons you feel so disconnected from others – and from yourself. Therapy will help you understand yourself better and will help you develop a more honest approach to life. You deserve to be able to look in the mirror each day and feel that you are a person with integrity. It’s lonely in that shell of yours. I think you also deserve to have help developing into the kind of genuine person you want to be. I searched the web for mental health services in your city. There are several centers that offer the full range of psychiatric and counseling services. Please ask your doctor or someone you trust for a recommendation.
I wish you well.