I think I might be a cuckold

Hi everyone—for the past two years or so, the thought of my girlfriend getting fucked by someone else has been driving me crazy. Just thinking about it makes me tremble, but I’m too scared to talk to her about it. I trust her 100%, but I don’t want her to walk out of my life. I’m not interested in other girls—only her—but the thought of her sleeping with someone else doesn’t make me jealous. What should I do? Are there people who’ve managed to do this? Tell me, how are you doing? And what’s it like to be a cuckold?