When my mother married my stepfather [I was 10] we continued to live with my Grandmother who I'd lived with for most of my life. We lived there for a year, I was happy there.
Then we moved not too far away, thankfully, to be a 'family' as my half sister was on the way.
That's when it all started to go seriously wrong for me. I had to let stepfather adopt me when I didn't like him much [he wasn't interested in me either then...he was later!] but wasn't told there was an option and that I could have said no. Mother was stressed to the eyeballs running a house and finances. Stepfather kept packing in jobs, mother then had PND, deep down knew she had married someone who was not making her happy and I was sent to an awful secondary school.
Things got worse and worse over the years and really affected my mental health. I wished so hard that I could go back to live with my grandmother who I adored, and where I was happy and loved. But other family were then living there so impossible even if it had been allowed.
It was the worst move of my life. The only saving grace was I could go to my grandmothers any time, and I did. She knew things were wrong at home but her door was always open.