Recently we celebrated my mother-in-law's 89 birthday. We all got together and celebrated over a weekend and went out to dinner multiple times. We decided to split the bill between her 3 children, each time we went out. The bill was often for anywhere from 14-18 people. Close friends and grandchildren were included.
To my surprise, I found out that both sisters were using credit cards that were tied to my mother in law's bank account. In essence my mother in law paid for their portion of the bill, and my husband got stuck paying the share of the bill with our own money.
I know my mother-in-law. If she had known she paid for 2 of her children and not the third, she would have paid it all.
She doesn't know they used her account to pay. When she see the bill, she will assume she paid it all including my husband's portion.
Am I being petty by being angry? I don't want upset my mother inlaw with this. But is there anything I can do? It seems awfully unfair to her son and the sisters to their brother.