This is the thing. You probably have a legal right to live in that house, and perhaps have some equity in it, who knows. He would have to go to court to evict you, and I doubt he could as you have been the stay at home parent. I'm not a lawyer or anything, so I could be wrong about this stuff. But, if you leave without checking this stuff out, you are likely giving up any rights you have.
PLEASE talk to a lawyer before you do anything....!!! Here's an excerpt from a page I found on the web: "More recently, in D v. R. (2003 N.Y. Slip Op. 23711, N.Y.C. Civil Ct., 2003), a court held that a non-married couple of ten years, with mutual children and contributions made to the home’s value, had acquired rights similar to a married couple as it affected occupancy rights of their shared residence. " This was from http://www.lawny.org/lawny/index.php?option=com_content&task=view&id=137&Itemid=75.
There is a bit more info there, especially toward the end, that is worth reading. But it isn't exhaustive. It is suggestive enough, though, to show that you REALLY need to see a lawyer. It is probably especially important that he moved out and left you and the kids there, so be sure to mention that.
Also, even if he is on the apartment lease as the guarantor, if your rent doesn't get paid I expect that your credit rating takes a hit.
Take care, Oldtimer
(Hi GH, glad to see you are doing well :-)... I'm great, but have a nasty cold, hoping Newtimer doesn't get it...)