Have you heard of the boiling frog analogy?
If you put a frog into a pan of boiling water it would jump out. If you put it into a pan of cold water it would stay there, then the heat gets turned up, little by little, it becomes uncomfortable for the frog but it's happy it its familiar pan of water, it gets slowly hotter until it's boiling but it's happened so gradually that the frog doesn't realise.
Abusers are charming and manipulative. They start off with the flowers and love and romance, they draw you in, get you hooked. Then they get a bit grumpy because the dinner you made is too cold. You blame yourself, apologise, warm it up, you ask yourself how you could be so useless as to serve cold food! You don't want to upset this prize of a man who clearly loves you. You start fretting about the temperature of his food. The next time the food is cold, he gets really angry, he works hard all week and comes home to this!! How can you be so useless? Other men wouldn't put up with this! You're lucky he's still with you!!
You blame yourself etc etc but it's not just about the food. The children are too noisy, his trousers aren't ready, the MOT is due, you haven't hoovered.
But he tells you he loves you and you believe him. He's great with the kids! Other people respect him and envy you. He's brilliant 95% of the time!
The trouble is the 5%. The knot of fear in your stomach, not wanting to upset him, not telling him things in case he gets angry. You are nervous, anxious, walking on egg shells.
Most abused people do not realise that they are being abused. It happens incrementally.
For most people the name calling, the swearing in front of the DC, the verbal abuse, those are boundaries, lines that cannot be crossed. Most people with healthy boundaries would walk away if those lines were crossed. Your idea of "normal", your idea of what a "healthy relationship" looks like has become distorted. His behaviour is totally unacceptable to most people.
I understand because I was in your situation. Terrified of coping on my own, not knowing how I would survive financially etc. But I did it and it's the best thing I ever did. I am so proud of myself. Check out the benefits calculator linked above. Plus he would have to pay you maintenance (I think it would be 25% of his take home pay with 3 dc and it's not taken into account for tax credits etc)
Your DH is nasty and swearing at you, name calling in front of the dc, that is exposing them to emotional abuse, it is not acceptable. At all.