Don't react ...this will throw him completely off balance ...you can of course cry in private but don't let him see ...don't rant and rave, don't do anything ...ignore him unless he physically hurts you ...then go to the medical centre and show them the bruises ….and ask them to make a note on your records.
THEN meanwhile, rationally collect everything you have relating to costs, expenses, income, outgoings, things you may have paid for or contributed to during the marriage and keep these in a locked file somewhere he cannot find them. This is 'evidence' of your contributions the marriage (also consider whether you gave up your career for him,etc) and once you have calmly and rationally sorted out all this paperwork, along with a note of his episodes of unreasonable behaviour and verbal abuse, you have enough to consult a lawyer if you wish. I would not imagine, from what you say he would be prepared for counselling ….
I know this is hard (been there, done that, had the bruises and broken bones !) but as you have two properties, it could be time to move out permanently into your chosen one. Once, and only when, you have had time to consider all this, and to look at what you could do as regards to affording to live on your own, (he will in all probability contest a legal division of the properties ….but you can take a lawyer's advice on this) and how you can live your life alone. You could mention to the children you and he are going to be living separately for a while ...after all they are adults ! If you can, wait until after the wedding ….give you more preparation time ! DO NOT TELL him what you are doing, i.e. preparing yourself. IF meanwhile he leaves ….then good ! Please take care and do not show him how upset you are by the accusations ….next time he accuses you about affairs, etc ask him to get checked out medically as well …..he may well go mad at this, but just explain tongue in cheek he may have passed it on to you ! If he is violent, you cannot put up with this and can call the Police ...that may make him think again Believe me, you CAN make a life for yourself ! ALSO as has been suggested, although going on for some time, he may have underlying mental health issues …….my late (second ) husband has Parkinson's disease and vascular dementia which made him violent and aggressive …….see if you can ask him to get checked out !