I'm gong to leave the debate about whether or not this is the right thing to do (impossible to tell from just the word 'controlling') and treat this as a woman fleeing an abusive situation in case it is of any use to anyone else.
You could get him to leave the house, but unless you can afford to keep it on your own income, it probably isn't worth it TBH. You don't want to have him holding power over you because you're relying on him to pay mortgage or rent.
Sort out your accommodation. Get any post relating to the new accommodation redirected to your workplace/a friend so that he doesn't know you're doing it. Continue to have your normal post delivered to the marital home but have a redirection set up ready for your leaving date once you have it.
In secret, gather all the documents you will need to take with you. Copy anything you think you might need that isn't yours (e.g. copies of savings accounts in his name, mortgage documents showing that both your names are on it, etc). Take that to your workplace for safe-keeping or leave with a friend.
If you think it is safe to do so, pack a few of your and DCs belongings in bags and stash them where they won't be noticed. ONLY do this if you think it will go unnoticed.
Go to see a solicitor and go as far as you can with getting a residency order in place without letting your H know. You can resume when you move. By the time it goes through, the children will already be residing with you and maintaining the status quo is 9/10ths of it.
If you're moving out of the area, as soon as you have your new address, find a new school and set the wheels in motion for your 4-year-old. Tell the school that you are leaving an abusive relationship, setting up a residency order and that they are not to disclose your new adress to your DC's father if he tracks them down. As he has parental responsibility, he is entitled to know which school your 4yo goes to and to contact the school about your child, but he is not entitled to remove child from premises if you have a residency order, nor is he entitled to know where you live.
Phone tax credits and child benefit etc as soon as you have your new address. It will take a couple of weeks to set things in motion, so get the ball rolling as soon as you can. You can't set things up in advance but if you treat the day you get the keys as the day your new life starts, you might claw back a week or so.
On the day you wish to move, arrange for removals to come once he's left for work. If he doesn't work, ask for a police escort on the grounds that you are fearful for your safety. Take only what you can pack and transport there and then so you don't delay. Yes you will have to leave some stuff behind, but that's part for the course in most breakdowns, let alone one where you are fleeing.
Arrange a supermarket delivery order, including nappies etc, to be delivered to your new address on the day you move in.