You can't get someone "off the mortgage".
You have to purchase their share of the property, paying for it using your own mortgage (so a new sole one, not the current joint one). You can't do this without his knowledge and consent.
Other options are 1) he purchases your share of the property and you move out, getting a mortgage to purchase somewhere else or renting. 2) The property is sold to a third party and you both move out to live elsewhere, separately.
You can't get away from the abuse whilst you are still in a relationship with this man, you have to split up.
Your home is already "broken" because one parent is abusing the other.
Your DC already doesn't see their father majority of the time. So only seeing him EOW if you split won't change much in a practical sense for DC.
What will change is DC not having to witness what's going on. Of course they'll notice your change in behaviour whenever your partner is around, they'll hear his comments, see both of your demeanors - him domineering and you diminishing yourself to attempt to appease him. You can't effectively hide it.