The Pain of Losing a Parent

After returning home from college, I discovered my dad was having an affair. Within the next few years, he had developed an addiction and disowned his family. My mother was devastated and my siblings and I were left to pick up the pieces. Several years later, she was dating. It moved fast, like from meeting online to married in under a year. He seems to be a kind man and is good to my mom. She seems genuinely happy and I'm thankful for that. But I cannot stand him. Even more than the emotional overstepping, his very existence is the reminder to me of so many griefs in my life.