If your husband is signed on the mortgage as you suggest, he is liable to the bank to make the mortgage payments just as you are.
However, since you are occupying the home and he is paying rent, you should cover a more substantial portion of the mortgage payment.
The exact amount should be determined by examining all of the other financial and other considerations that are being proposed as a result of the separation.
If you are living in the NYC metro area, please call me to arrange a meeting for the 3 of us to discuss this matter in greater detail, and to work out all of the many other issues that must be agreed upon for the separation to work.
Leonard Weiner, Esq./Divorce Solutions