"Is it true that absence from the country you were married in for 15 years nullifies the marriage?"?

When we met he was going through a divorce here in Miami Fl. Soon I found out that he was also married in his native country of Cuba. He left Cuba fifteen years ago and left a child which was a year old at the time. He got divorced here from the woman he was married to in Miami, but he is still married in Cuba. My question is…is it true that by being away from his country for 15 years he is considered not longer married…what could happen is the wife from Cuba decides to come to Miami, what are her rights…and her childs who is 17 now…what happens if the child turns 18 in Cuba and later migrates to USA…what happens to our marriage…

Please I really need your help, obviously his wife from Cuba does not want to give him the divorce…what can we do…