Welcome to Wiki. I am sorry to hear about your problems. Does your stbx have a solicitor?
Finances on divorce are worked out on the basis of need. To tell you what we think is fair, we would need a bit more information
Ages, length of marriage inc any cohab, ages and genders of children, respective incomes inc benefits, value and size of FMH, outstanding mortgage, pension values, savings, debts in sole or joint names.
Are you cohabiting with your new partner? Would she sell her place so you could pool resources? NB if you did, you would need to protect your respective shares in the property.