disable auto update?

hi WP friends, Im a WP user, not understanding programming language, which works fine most of the time

All my sites are in WordPress, and Ive suffered an enormous damage in connection w. auto update, 4.3.1, that destroyed themes and plugin setups

It takes soooo many hours of my life to try to repair this damage, in this case replace all themes and start from scratch – and chances are that it will happen again any time, as I have no control of the update parameters

SO, Im looking for advice, as I like the WP platform, and spend a lot of time learning and building sites – but, Im ready to quit, and look for an alternative, as it seriously damages my work and life quality if I have to start over at random.

Does someone have some fresh advice?
Thank you in advance
greetings