You have said several times that you are very scared of your partner. That fear is well-founded and also has absolutely no place in a relationship. My DH and I have had some fierce arguments over the years. I'm not remotely scared of him. So it's great that you've realised you need to get away. He's been in your head all these years minimising and normalising abuse (there's a book about this: In The Mind of the Intimate Male Abuser: How He Gets Into Her Head) so it's great that you're able to see so clearly now.
As regards therapy - I think the people who are recommending it mean for you to have therapy alone. It is a very bad idea to have therapy with an abusive partner - it should never be done.
As to his public reputation - it's common for abusers to build a very respectable public reputation, it's like a smokescreen. But that doesn't mean that in the moment he won't lose it with you and do serious physical harm to you and/or your children. As PP have said, abusers are at their most dangerous when they sense they're losing control. For this reason - KEEP YOUR PLANS SECRET, do NOT tell him what you're doing. You need to get out first. Your and your children's safety is the most important thing here.
Women's Aid has lots of useful information (www.womensaid.org.uk/the-survivors-handbook/making-a-safety-plan/#1447926965295-8f67f8a6-62c7) including how to pack in order to flee an abusive relationship and about having an emergency bag with all the most important things packed away. If you can safely keep and store an emergency bag that would be worth doing. Another thing some posters have talked about doing as they plan their escape is saying they're having a clear-out, putting things in binliners and taking them to a friend or family member to store.
But in the end, documents and things can be replaced. You and your children can't. So prioritise getting yourself and them out safely.
With that in mind, remember to wipe your browsing history every time you look up something related to getting away including your mumsnet browsing history.
I have reproduced the Women's Aid list below for your ease of reference:
"Ideally, you need to take all the following items with you if you leave. Some of these items you can try to keep with you at all times; others you may be able to pack in your “emergency bag”.
Some form of identification
Birth certificates for you and your children.
Passports (including passports for all your children), visas and work permits.
Money, bankbooks, cheque book and credit and debit cards.
Keys for house, car, and place of work. (You could get an extra set of keys cut, and put them in your emergency bag.)
Cards for payment of Child Benefit and any other welfare benefits you are entitled to.
Driving licence (if you have one) and car registration documents, if applicable.
Prescribed medication.
Copies of documents relating to your housing tenure (for example, mortgage details or lease and rental agreements).
Insurance documents, including national insurance number.
Address book.
Family photographs, your diary, jewellery, small items of sentimental value.
Clothing and toiletries for you and your children.
Your children’s favourite small toys.
You should also take any documentation relating to the abuse – e.g. police reports, court orders such as injunctions and restraining orders, and copies of medical records if you have them."