I'm not okay with sharing a bed with my girlfriend's friend who sleeps next to her while they engage in sexual activities, making me feel like a cuckold

My girlfriend moved her best friend into our home, and now I\'m stuck sharing a bed with him. His constant late-night escapades with my girlfriend are driving me wild. I can\'t take it anymore. I need to see it for myself. Maybe then I can move on from this unbearable situation.