Can I sue my ex-fiance for my contribution to a home that we purcased together although we never got married?

I've been in a long term relationship with my children mother for nearly 20 years or more. We purchased a home together with only her name on the deed because the realtor suggested we only use her income because I was self employed at the time. We have been apart and the dependents moved in with me - and I avoid collecting child support to give her room to maintain the home with my eldest son until the market rose again after falling. Now she is refusing to sell or give me what I know and she knows I am deserving of. I payed off her car loan so that we can qualify for more and I personally spent monies on rehab to raise the value of the home. I never thought I would be in this position - I REALLY TRUSTED HER - and now I see that was not a good thing to do. I am wondering what are my options? I live in upstate NY. Thanks!