If the mortgage is only in your husband’s name, then he is liable for making payments. If it is a joint mortgage, then both you and your husband are ‘jointly and severally’ liable, meaning that you are both responsible for any payments.
If your husband is refusing to provide any financial help, you should take legal advice. Once you have started divorce proceedings, you may be able to apply to the court for interim maintenance. If the court decides in your favour, your husband will be legally required to pay the amount the court decides.
If you have children, you can also ask the Child Maintenance Service to work out how much child maintenance you are entitled to and collect it for you. At the same time, you should make sure that you are receiving all the state benefits to which you are entitled.