Another poster here to reassure you that the children can and do come out of divorce happy and well adjusted.
Like others, I stayed in my emotionally abusive marriage for about 5 years too long for fear of leaving. Financially I knew I would be ok in the long run as I was the main earner (massive problem right there are he never had a steady job) but didn't want to upset the children.
3 and a half years ago, I just snapped and walked out, took the children to my mum's and left. I left the house we owned (though upon which i had paid all mortgage payments) and all my possessions. Never went back. My only priority from that point on was to ensure that the dc's were happy and came first. We told them we were splitting together. Told them we didn't love each other anymore but we still loved them. (ie did not tell them the real reasons I had left). DS was 10 at the time and dd was 6. DS took it pretty much in his stride although was obviously devastated at first. DD took a little more time to come round and would refuse to go to her dad's and was very emotionally unsettled for about 6 months. But, with consistency and love from both of us she adjusted to the situation and is fine.
I have not once bad mouthed him to the children. He has many faults as a partner and a father and still fucks up being a father sometimes (forgetting to go to dd's sports day when he said he was going and I couldn't, didn't arrange for anyone to go because i thought he was....he was asleep....) but he does see a lot of them and they love him. He pays very little maintenance and I pay for everything for the children. As they get older they notice this but I do not pass comment.
The trigger I think was realising that I was not modelling a healthy relationship for the children. I underestimated how often they saw him shout at me/insult me, heard me cry, saw how unhappy I was. A dear friend pointed this out to me and I realised that staying for them was not the right thing for them, quite the opposite. Within a couple of months, ds even said how much happier I seemed.
Fast forward to now and I have an amazing new partner who is literally the complete opposite. I am modelling a healthy relationship, i have lost weight, got fit and am literally a different person and the dc's are happy. They see lots of their dad and have a great relationship with new partner and his dc's.
Financially, please ensure you take everything to which you are entitled. I was the main earner so I got stung a little here as he got to keep the house but I got to keep my pension. The house hurt as there was equity and I still cannot get my name off the mortgage due to his poor credit rating. Plus i paid every single payment, paid all the bills, everything. You must make sure you do this for the sake of your future and children.
And fwiw....I call mine twatface
. Good luck!