In theory you could apply to become a Mexican after two full years of living in Mexico. Then the process of becoming Mexican could take another two years. You'd have to get an FM2 as soon as you move here. And once you've held that FM2 for two full years you can apply for citizenship by marriage. In Cancun Immigration doesn't usually grant FM2s to people in the beginning, usually they try to make you get an FM3 first. But legally you can get an FM2 without ever getting an FM3. So if you plan to live in this area you might try getting your FM2 from a different office than the Cancun INM office. If it were me I would talk to the famous immigration lawyer Mauricio Mendoza about this before doing anything.
