Honestly she is 16, still lives at home and is in school. She isn’t an independent adult.

It’s sad if she is treated poorly at home but you have no business to demand privacy in THEIR house. And most parents would not allow their 16 year olds go anywhere alone with a grown man.

I also think you should stay out of stepmoms and dad’s marriage (I don’t see how it’s your business if stepmoms influences dad’s decisions or not, their marriage is their private matter)

Honestly if you want privacy and do whatever you want with your girlfriend and if you want girlfriend who doesn’t need parental permission for anything, you should date an independent adult, not 16-year old.