I climbed out of a window after a secret meeting with my mistress
You did what!? Why would you need a secret meeting with your mistress?
I'm just being careful, I don't want to be caught, although I didn't do anything wrong, I know that my parents will cut me off financially
You shouldn't have a secret mistress, and sneaking around is bad for everyone involved. If you have to sneak then you should come clean and tell everyone the truth or else they'll never trust you again.
I really don't care. I don't like anyone in my family and I don't feel bad about the secrecy.
Keeping secrets like that will tear your family apart. You might not feel it's a big deal now but you need to realize this could effect you for the rest of your life.