HollyHunter18 sorry I didn't reply sooner.
My DS was not diagnosed with autism but I strongly consider he may have aspergers.
Anyway, his dad was a loving very involved dad - and has been far far too 'rescuing' of each and every problem, challenge, upset and difficulty faced by our DS in his growing up, in my opinion. I wanted our DS to learn to take responsibility, to learn from mistakes, to have the confidence to make a mistake and try again, to learn to respect other people's needs... he has learned little of this, in my view, because of his dad's chronic need to 'rescue' and protect him. Our DS now hates me because eg I ask him to unload the dishwasher, or help his dad, or come and visit his grannie.
But like you, the idea when my DS away from his dad when he was small, was not an option for me; they adored each other and still do (albeit in what I view as an unhealthy way).
To my shame, I have to say it was probably me who was contemptuous and critical far far more often than my DP was to me. My DP is a passive aggressive, people-pleaser, so the things that were making me angry were largely invisible to other people, like eg no sex for 15 years, no handholding, him not doing what he had said he would, him 'spoiling' the DCs, him having secrets from me... all of which mean I am the baddie in our household.
I would, if I knew then what I know now, have taken the harder road and moved the DCs away from their dad, and tried to co parent while apart. I'm living in a mess that I was too scared to deal with when they were small, and now, 20 years on, it's a bigger and messier mess than ever.
Good luck - trust your instincts.