I'm the baby of my family with two older sisters. My Parents have been married for 30 years, and we've all been very close my entire life. I won't go into the details, but I recently found out my mom was cheating on my dad. I was utterly devastated and immediately went to my sisters to seek comfort. Surprisingly, they didn't react the way I was expecting. I was full of anger, but they seemed to be more understanding.
Eventually after a lot of prying and crying, they revealed that my father had an affair with some woman for nearly a decade. Apparently things had come out about five years ago when I was still in high school — I do remember a strange time during my junior year, but I didn't put things together. My sisters had talked about it with both my parents, but they had all decided not to tell me. Obviously my mom chose to stay, and I think the same will be said of my dad after this new turn in events, though apparently their relationship is more "open" then I realized.
Ever since my sisters broke the news to me, I feel like everything I had ever thought about my family was the exact opposite. I can't believe that my parents were willing to put our family through this, and I'm terribly angry with my sisters for collaborating with them to keep this lie going for so long. I have never felt more naive and hurt. They've all tried to contact me, but I feel so much hate towards them right now, I just can't let them in. I don't know what to do. Should I try to learn to forget their terrible betrayal and forgive them?