You can reaffirm any secured debts you want, so keeping one house is not a problem.
I would contact an attorney though and speak with him or her. Little details like that can cause problems if you file yourself.
The trustee has ultimate say over what you can and cannot reaffirm. That goes for homes, cars, or any of your debts.
If you have two homes, and by selling one, the equity would allow for payment of some of your creditors, then plan to lose the house. The same thing goes for your primary residence. If you have enough equity that it exceeds your homestead exemption (varies by state), you may be forced to sell your home, in order to use the equity to pay off your creditors.