I'm mad at my mom for having a fuck buddy
Why are you mad at your mom for that?
I dunno. It's just weird and makes me uncomfortable.
It is sometimes difficult to treat parents as individual people and it can be upsetting when they do things you don't like. But it is better to accept it than to get get angry at them.
Waaaaah, I'm going to go crazy on her.
I know it can make people uncomfortable to imagine their parents in sexual situations, but your mom is her own person and is free to do what she wants. If she is single, then she is free to do what she wants. You shouldn't judge her for that.