We are splitting up - I want to sell the condo, she refuses to sell - what are my options?

Hi we are an unmarried couple living in New York City. We have been together for 10 years and have a 8 year old son. We have agreed to split amicably. However, I want to sell the condo (primary residence) and she does not. She is adamant that she is not ready to move. I pay the mortgage (which is about 3/4 of my monthly take-home pay) and she pays the maintenance and all other bills. We share food shopping, child care and similar expenses. We are co-signers on the deed; my credit is great and hers is lousy but the mortgage has PMI because I own another condo (separately, it's all mine) and I couldn't buy our condo without her co-sign. She can’t afford to buy me out (or so she says). She even suggested that I move out, and she stays and gets a roommate (everyone says this is ridiculous, especially considering impact on our son). I feel stuck and I am going out of my mind. What are my options? How do I get myself out of this? Thanks, RT