My girlfriend is on my deed, but she is not on my loan. What happens if I we split and I want to sell?

She owns and undivided 1/2 interest in the home.  You probably added her to title after you had a mortgage in place, consequently the lender may accelerate your existing mortgage because the lenders have a clause in every mortgage specifically stating that they may accelerate a mortage for many reasons, one of which is --your case, adding an additional owner of record.   If you split and want to sell, you need her to sign off of the deed.   If she did not put any money down, I would find the right time and explain to her that if the lender finds out she's wrongfully on title, they may force payment on the entire loan -- this might be a nice way of getting her to sign off.   Lastly, you may be upside down (owe more to bank than what the property is worth) and if this is the case, you may want to see a loan modification specialist such as Manning Law Offices in North Providence.  Good luck.