Islamically, once you are divorced from someone, he becomes your na-mehram. So you should not be living under the same roof anymore, especially if it is just the 2 of you living in that house. However, if you guys live with your parents (the girls parents) and her father or brother live there as well, then its ok Islamically speaking if the 2 no longer have any contact. But why would you want to live in the same house as your ex-husband?
Another thing, some folks are constantly trying hard enough for us to realise the fact that they're oh so dumb to not understand the context of the question asked. I bet the OP is somewhere laughing hard over it all. So am I, all day today. haha. :-)
When a husband divorces his wife, the wife has to live with him in that house. And, the husband has to provide for her maintenance. This goes on for three menstrual cycles. If she's pregnant, then she stays until she gives birth.
Better to ask a scholar for the details, InshaAllah.