Feels like I'm losing the kids

With all due respect you have no idea what it’s like living with an emotionally and verbally abusive man who uses the kids like this. You often need to do whatever it takes to ensure the kids’ welfare

They don't like the man, they're having trauma inflicted on them and are desperately appeasing their abuser.
Their developing brains will be flooded with cortisol, read up on how this impacts people for life.

I don’t think “manipulating” kids who are already experiencing domestic abuse is good advice.

kids need love, security and boundaries not a double head fuck by two different parents.

1. Do not apologise when it isn’t your fault. Seeing you say sorry makes the kids think it’s your fault. If you need to leave an argument tell him you will not speak to him when he’s swearing at you and walk away. I assume he doesn’t hit you but if he does then you should leave with the kids now for a women’s shelter.
2. Seek legal advice. Solicitors will often advise you to find out as much about the family finances as possible before filing for divorce. For custody if you don’t work and he does then you will automatically start with more custody at this age with the view of it turning to 50/50. But often it’s better for you to start at 50/50 so you can find work. If you’re worried about him poisoning the kids against you then the solicitor can give you advice about that too as the court system takes a dim view of this.
3. Start preparing to leave him. Let close / trusted friends and family know and try to get their help. If you work and have your own money begin to look at rental properties - estate agents often have special procedures for vulnerable people like you and will keep all correspondance at the shop if required.
4. This is a bit sneaky but imo start building an amazing 1-2-1 relationship with the kids as you plan to leave. Manipulate them into thinking you’re the best parent by giving in (temporarily) to what they want, giving lots of cuddles, taking them out, doing special things with just you. Kids aren’t stupid. When they realise mum can be just as fun and lovely as dad (but without the shouting and swearing) they will naturally come to prefer you. Don’t fall into the trap of being strict with them because he’s indulgent.

You are not losing them, so there is no need to cry over yourself anymore.

Now do what’s best for them and for you and get away from their abusive father.

You should consider the trauma they are experiencing in these moments and use it to fortify your strength to leave

Look up fight flight freeze fawn. You’re not losing the kids they are displaying a fawn response to an abusive situation. They are young but already learning to protect themselves by fawning and appeasing the person who is a threat.

Oh goodness. Well for starters I'm glad you know you have to leave. Who do you have supporting you - parents, siblings, friends? Do they know what's going on? Now's the time to lean on them for moral support.

I would try to respond to H saying these things by just repeating broken-record statements like "it's not ok to speak to me like that," "I'm not listening to you if you can't be civil" etc. It's not engaging with him and it's modelling to your kids that we don't put up with this.

Definitely leave as soon as you can. You won't lose them. You will also be a cool, fun parent when you don't have this awful ball and chain around your neck!

They are 3 and 6 - They do not have any say in the matter!! You are their parent and have to do what’s best for them so take some control back.

You’re more likely to lose them if you stay because they’ll grow up speaking to you and other women the same way their dad does.

Do you have any family you can go to when he’s at work? Call a domestic abuse charity for their advice? You need to do something asap.