OP I think the thing to realise is that YOU are not alone, nor need to be.
You do need to talk to someone OP, and I would ring the rape crisis centre for support for yourself.
You have small children and pnd, and you are not getting anywhere quickly by keeping silent about this, and also keeping your DHs secrets.
Would you go to your GP as well?
There are two people in a marriage, and it is the duty of each to stay as healthy as can be. Till death do us part depends on each partner doing their utmost best to deal with all health issues that arise in order to keep engaged with the marriage partner.
Denying a horrific experience, being in denial, self medicating by taking class A drugs, and jeopardising a career and a revenue source for a young family, and telling everyone to be silent about it is not engaging with those marriage vows.
Please please op go to the GP and get some help for yourself, then ring the rape crisis centre for help for your DH, then narcotics anonymous for help with his cocaine use.
Your DH needs to be on board and engage or I don't see your marriage lasting even if you hide under a rock, and keep his experience and the feelings, and coping mechanisims he has about it a secret.
I think there's a high chance your marriage is over whether your like it or not. Keeping his secrets for him etc will hasten it's end.
Be brave, get help. You're not alone. Ring your GP and get an appointment.
Good luck!