I truly would expect a therapist to say that it's inappropriate and harmful - and impossible! - to provide relationship counselling and help a rapist and his victim to continue a romantic relationship.
It's like a stepfather and the stepdaughter he sexually abused for years going to family counselling to try to have a healthy relationship, because he knows it's wrong to keep abusing her, and he doesn't want to, and really, he loves her.
It's sick, and a responsible therapist would - I imagine - say that you each need therapy separately. Him to understand and regret what he's done (if it's possible, which I doubt), and you to understand and be angry about what he's done.
The relationship is a twisted mockery of marriage - it's been poisoned by him from the very beginning with his coercive control of you, his sexual 'boundary pushing' (aka assaults and rapes), his anger and outbursts, the way he's scared both you and the children, his exertion of his power over you (including the fact that you're so much younger and you now have 4 children to support - and he wanted you to have a 5th), his gaslighting, and more.
There's no turning this marriage into something healthy; it's a bloated corpse, and it's what your children are being taught is normal.