I just wanted to pop on, and tell you that I was in almost your exact position, some 13 years ago. Husband in high powered, high paid role. Refused to help during the night with either of the babies, even when I begged. Wasn't a bad Dad, but he wasn't faithful and had also tried to kiss all of my friends. It took me 4 years to leave him. At that point we'd been together for 20 years. His whole family refused to ever speak to me again, because apparently, what he had done was "just a bit of fun", whereas I was "splitting up the family". This was a deeply religious Irish Catholic family - nice!
Like your Husband, he turned nasty and tried to shaft me out of money I was owed. He pleaded poverty, and didn't want me to take my half of his pension. Tried to pay less child support than he was meant to, by lying to the CSA about his income etc. He actually managed to convince the CSA that he earned £34,000, when in fact he earned £134,000. He told me that "he shouldn't have to pay Child Maintenance to fund my life style". The way he spoke, you'd think I was a yummy mummy, lunching with the girls, driving around in a land rover, when in fact, I was working part time, earning £1200pm, and trying to pay all of the bills and a new mortgage from that, whilst paying for our food on credit cards. He also came out with weird shit, like telling me that the kids could go and live in his parents loft 350 miles away? I mean, WTF?
His family thought I was the devil incarnate for going after his Pension. Erm, he only managed to hold down that big job, with big pension, because I sacrificed my job and pension in order to be the present parent doing everything at home, so no, we both had a equal claim to that.
My solicitor drew up an agreement, whereby his pension value and mine were added together and divided by two. He then bought me out of the house and had to pay me in cash for the pension part. He was incandescent with rage at this. He hand delivered a note to my new address, pleading all sorts of poverty that would befall him, should I pursue this route. I held firm. A few months later, he moved his new GF in to the marital home, and bought new carpets throughout, new curtains throughout, a brand new kitchen, a new car and a foreign holiday. Poverty, my arse!
Anyway, please please spend money on a good Solicitor. Mine cost about £1300, but it was so worth it. Take everything you can get, because this is your one chance. Get half the pension. Take copies of his pay slips for the CSA. Get the claim in, if you haven't already.
I am now happily married to someone else. The kids do see their Dad for the tight fisted (for no reason) arsehole that he is. They do love him still, but once children are adults, they can really see things clearly.
You need a very good solicitor and a separation agreement drawing up, asap.