Your question reminds me of the Anais Nin quote “And the day came when the risk to remain tight in a bud was more painful than the risk it took to blossom.” My best advice is to follow your instincts. If you are thinking it would be a good idea to see a therapist, then see a therapist. Your fear of what might happen is holding you back from the possibility of getting better and in your own words: “for at least one person in the world to know who I really am.”
Since you have been hospitalized in the past, you are most likely familiar with the criteria that need to be met for an involuntary commitment. It varies from state to state and country to country, but the bottom line is that you have the thoughts, plan and intent to harm yourself or others and are unwilling or unable to agree to an alternative plan. It is quite common for mental health professionals to work with clients who have suicidal thoughts and I would say that it is rare for it to lead to an involuntary commitment. Our first priority is to keep you safe and help you feel better.
Take a chance on trusting someone to help you. You are worth it.
All the best,
Dr. Holly Counts