He doesn't help with household expenses. Doesn't pay for anything for DS and doesn't even want to hear about paying maintenance
Your solicitor has told you to move out and your stbxh will be liable for half of your rent? Is your solicitor one that was recommended to you by WA and has s/he told you how to get blood out of a stone ensure that he pays up?
If you move out you can put money on your stbxh dragging proceedings out for months, if not a year or more, before the house is put on the market and he won't pay a penny towards your rent.
A better plan would be for you to document all of his unreasonable behaviour as following you around, recording you, calling you names, threatening you, snooping, trying to turn ds against you is tantamount to harassment and intimidation, and provides grounds for you to apply for a emergency ex parte occupation order which will compel him to leave the marital home pending a full hearing of the case - this is usually within 4 weeks of the date of the ex parte order.
If you are still set on leaving, book moving truck for a day on which you are confident your stxh will be at work and take all of your own and your dc's personal belongings together with as many items of value as you can, plus all the essentials you will need - washing machine, dishwasher, sofas, tvs etc - to provide a functioning home for your dc.
Rope in as many friends as you can to help you and regard it as a grab and run exercise. Perhaps you could leave a webcam running so you can have the pleasure of seeing his face when he returns and realises his home is more than half empty.
Btw, make contact with your mortgage company, appraise them of the situation and make it clear that you do not give your consent to your stbxh subletting any part of the property.
If he gets tenants he'll have further excuse reason to prolong a sale as they will require notice before the property can be sold with free and clear title.