I am an international Physics PhD student who is currently finishing his second year successfully, with one publication and others in preparation. However, I have a problem that has not let me sleep properly since day 1 and I need to vent it out with you. When I applied, for some stupid reason I mentioned on my CV that I was a teaching assistant for two terms (in an area I am pretty good at) when in reality I was not. I won't go too much into details but I attribute this behavior to extreme low self-esteem and mental health issues that I have had since I was a teenager due to a very traumatic period in my life and more than lying with ill intentions to the admission committee in order to get an advantage I was lying to myself. I did not even realize what a horrendous mistake I had made at the time, and it also did not help that nobody from my former lab checked my CV before I sent it. As a result I have been in therapy since 1 year ago to understand the causes and threat my compulsive lying and me and my therapist believe that I have made important progress.
I don't think the lie was important for my acceptance (the PhD is 100% research based without coursework and teaching duties) and scholarship and every other part of my application was 100% truthful (1 publication at the time, top 5% of my cohort, outstanding letters of recommendation, internships, academic awards, etc) but I still can't get over what I did as I feel extremely bad as a person and also fear every day that I will somehow be caught and get expelled or get my degree revoked in the future. My supervisors are the most competent, intelligent but also the most kind and loving persons I have ever met, so while I have wanted to come clean for a long time I don't want to disappoint them. Besides, I have improved immensely as a person while living abroad in this beautiful country and have never been as happy in my life; I honestly think that getting expelled would have horrible consequences for my mental health, future dreams and finances and God knows how long it would take me to recover completely if ever. What do you recommend me to do in this case?