separation agreement and sale of house

[swim]

I am separated after 13 yrs of co-habitation and marriage. I am in the matrimonial home one 22 yr old living at home and one child at home for summer back to college in the fall,ex is making mortgage payments. Was approached to sell house by private buyer but I won't sign until we have a separation agreement in place as monies will be tied up in trust and I will not have any spousal support. Great disparity in our income 143k my ex and 23k me. My lawyer has said don't sign and push to resolve separation agreement (of course spousal support is the sticking issue). His attorney is now threatening to get a court order to force me to sell. Need advice on how to go forward with this?