Is someone paying the mortgage? If not, then you don't have to worry, the foreclosure will remove both your names.
You can't just force him off for not paying. You can ask him if he'll quit claim his interest over to you, but he would be stupid to do so if he was still on the mortgage. If you want to keep the house, I'd arrange a refinance as well.
This is why it is stupid to buy property with boyfriends/fiances, etc... Divorces are easier to obtain than splitting up property/mortgages.