I've Been Faking Orgasms For Years

My husband thinks I have amazing orgasms every time we have sex, but the truth is, I've been faking it for years. I don't know why I started, but now I can't stop. I feel guilty and ashamed, but I'm too scared to tell him the truth. I'm afraid he'll be disappointed or think there's something wrong with me. It's not fair to either of us, but I don't know how to break the cycle.