Back when I was 15, my mom told me that my dad has been having an affair and had a secret child with this woman. I was weirded out and disgusted and angry, but weirdly, at the same time I was kind of excited to find out that I had a sibling....anyways, my mom made it crucial to me that I do not tell ANYONE about this because she didn't want family members to talk or feel bad for her. My two best friends that I loved and trusted with all my heart happened to be my two cousins, I told them about the affair and about my secret sibling. I not only told them but I also told my other best friend which happens to be my neighbor back in my homeland. Now fast forward to right now, I'm 20 years old now turning 21 in September, and I can't stop feeling ABSOLUTELY TERRIBLE about telling them about my family secret. I feel like I completely backstabbed my mom, I feel untrustworthy and terrible and the guilt eats me alive to the point where I can't sleep at night, nor eat. I no longer speak to one of the cousins I told, and I told my other cousin (that I do still speak to) that I was lying about the affair and I only told her that because I wanted her to feel bad for me and blah blah blah. I can't stop feeling horrible, I was such a stupid person when I was 15-17. I didn't meant to hurt my mom in any way.....I feel like telling my mom and asking for forgiveness, but my husband says that by doing so, I would be benefitting myself only, and she would be hurt....how can feel better? Have you done anything similar? I feel terrible ugh

UPDATE: so I told my mom...she's upset ugh. But i got it off my chest.....what should I do or say to make my mom feel better ?