So many parents are better the second time around, and it’s bittersweet. How many times have you heard this story before? A mom had her first kid at 20 when she was young, dumb, and making everything up as she went along. Then, 15 years later, she has her 2nd kid and is able to give that kid everything her eldest never had. While the eldest might be glad that their sibling is growing up in a more stable environment than they did, they likely simultaneously feel bitter that they never got to live in a nice house and feel financially secure their entire lives. It’s a perfectly normal feeling. 

These kinds of resentments don’t only happen in nuclear families. If you have a blended family, there’s a huge chance that a kid will be resentful of their parents starting a new family with new kids that they don’t know or care about.