Sister refuses to attend family vacation after discovering her sisters expect her to cover ¼ of the cost, despite being the only sibling without kids: 'It is unfair to charge me the same as a family of 4'

As the only person in my family without kids of my own, I know how divisive that little detail can be. Being the only single person in a family, the only one without a core family of their own, can be quite isolating, and in some cases, can be expensive as well. 

Take the woman in the story below as an example. Her family goes on a family getaway every year, where they rent a house on a lake and enjoy their time together. However, out of the three siblings, she is the only one without a partner or kids, and this year it is causing a divide in the family.

You see, both her sisters require more than one room in the vacation house for their children. But when the bill for the vacation came in, the family still split it four ways, completely disregarding the fact that their single sister is only one person, and shouldn't pay the same amount as a full family.

When the single sister brought this up, she was shot down, and now she considers backing out of the vacation altogether...