Nope, no obligation to get over it
Dear Prudence,
When my ex and I were married, we had trouble conceiving and years of heartache. I thought our marriage was strong enough to survive this, then I discovered he was having an affair with my sister. We had a huge, traumatic confrontation and my then husband and I decided to move and make a fresh start. A few weeks after we moved, my sister gave the news that—surprise!—she was pregnant. My ex then divorced me to start a family with her. Because I’d just started a new job and had a mortgage, it was financially impossible for me to leave. I stayed in the new city by myself and eventually made friends and settled there. My parents were also very hurt and angry, but when the baby came they mellowed and reconciled. My niece is now 5 and I have never met her. We take turns attending family functions because I can’t bear to be in the same room as them. Recently my parents gently asked if I would consider having a Christmas dinner with my sister. I told them I would think about it and I really did. I took a deep breath and went on my sister’s Facebook page for the first time. There, I saw hundreds of happy pictures of them as a family. My ex-husband kissing her after she’d just given birth, photos of the happy first birthday party, family trips, etc. She was tagged in a status update from my ex: “Celebrating another amazing anniversary with my beautiful wife, thank you for giving me so much happiness and our perfect daughter.” I literally vomited after reading that. After five years, is it time for me to get over it and try to force myself to at least tolerate their company?
Re: Nope, no obligation to get over it
Your parents have a desire to smooth things over but...what about your needs and feelings? You were betrayed by two people you should have trusted the most. Tell them that you are not in a place where this is possible.