A letter to my mom

For context: D- 45 A- 41 F- 38 me- 28 (years old ) Mom, our whole life, well, me A & F's whole life, you told us A's dad was dead. They knew their dad wasn't dead and then 2 years ago went on a DNA tracing website and found out that not only their father is alive and well, but we have another sibling, D, that you put up for adoption at 16, forced by your parents. I can understand it was all hard for you, but was it not painful for you to hold all that in for so long? Even now that we all know, it isn't talked about, ever. What if A never did the testing? Would you have ever told us? I'm glad you're in contact with D, again, but I wish that you had been honest with us about it all. Now I wonder what else you're not sharing with me... Me specifically.. both A and F have come to me before and told me that you didn't want me to know about upcoming trips, etc. worried about how I may react.. how am I supposed to react to this?