From the FAQ:
"Can I have more than one wife in prison?
All states within the country have laws prohibiting polygamy, but there is not a national registry that tracks such things. In theory, one could have an incarcerated spouse in all six of the states that permit conjugal visits, as well as one or more additional spouses who are not in the prison system. Such behavior would be highly unethical, moderately illegal, and recommended only to interstate truckers, airline staff, and those who have the ability to fully reap the benefits of such an arrangement. While we can not endorse such behavior, we would not be aware of it unless you told us it was the case, and we'd have to recommend you only select one of our Lifer packages in order to insure that none of them would be released unexpectedly. "