How can I get him to pay for debt

My ex partner and father to my children, kicked us out of our family home in 2009. The property/mortgage and land registry is in his name, there is a declaration of trust as I put the deposit on property. and earlier that year we made improvements by putting a large conservatory on property which was financed which we both signed but agreed to come from my bank account. Currently I am still paying these payments and Im really struggling. At one point he agreed to pay towards unto a settlement was agreed but he did not pay and incurred further charges. I was put on a payment plan for 12months but this has now finished. i am privately paying for a solictor and dont seem to have got anywhere and just seem to be costing more and more. I would like to find out my options and hopefully find a clear way forward. I have a good job and would like to to be able to buy a property for myself and the children and begin to be settled again. I would prefer not to go bankkrupt as it is not my debt.