You can read more about aldara, including indications, by clicking http://www.3m.com/us/healthcare/pharma/ ... view.jhtml
One thing that's mentioned there is to make sure all the cream has been removed prior to having sex. Note that Aldara may weaken condoms.
Transmission studies among couples who share HPV are lacking, so there's no hard data we're aware of to give, but most experts we're familiar with think it's unlikely couples that share HPV will "ping pong" it back and forth in a cycle of reinfection. Some studies suggest (hard to say "prove" at this point) that when such couples use condoms, they might have both warts and the underlying virus clear a bit more quickly - just why this happens isn't clear.