Sexual assault is a crime, and so is coercive control.
The first steps are to call the GP, explain the situation and ask to be referred for NHS counselling support. Bluntly the lists are so long this is unlikely to achieve much in medical terms, BUT it will ensure the situation at home is recorded in your medical notes, which is vital.
Then you need to ask to speak to the school's pastoral lead, and to explain what is happening at home so the children are supported, and there is a record.
Then you call Women's Aid and ask for help. If they tell you to report him to the police, do that. But be led by them - they are the ones with vast experience, sadly, in domestic abuse.
You need a record of what is happening because legal aid - free legal support - is not available in most family law cases now. You can ONLY get it if there is evidence of domestic abuse. You need the school and your GP aware so the kids can be supported, but also so you can have legal support down the track if you decide to leave and he tries to use the children as pawns or weapons against you. You won't get it otherwise.
The legal support won't help with financial matters, but it will help in child arrangements orders, and with an abusive parent in the frame, that support is really, really essential.