Hey all, i need some advise! im panicing!

Basically, I have perm residency (im british live in UK) I have this visa as a dependant, my mum and dad applied a few years back, dad is skilled and I got it as a dependant.

Mum dad and bro have made the move, myself and my boyfriend (also english) went over and stayed with them for a few months, have no returned, living at his parents and are desperate to go back and start a life in Oz close by to my family.

Can we apply for Defacto even if im a dependant (or was at the time of application) of my dads visa? or does applying for defacto or fiancee mean I'm no longer dependant, therefore scrubs out my visa?

please help we are trying everything possible!!!!!