My boyfriend and I bought a home in 2003, we want to separate but he doesn't want to sell the house, he just want me to get out. what can be done?

we bought a home in 2003. Both of our names are in the deed. He paid the mortgage and I paid the utilities. We want to part ways but he won't sell the house, he just wants me to get out and give me 40.00 or 50.000, when the value of the house is at least 350.000. I'm willing to take 1/3 since he paid for repairs, although I paid for other improvements also. What do I need to do to get either a mediator or take this to court. Thank you.