I'd try to make the girl got pregnant from the other guy...once she have 3 daughters, i kill the other bastard. Now I have one dude less to use my natural resources, 3 girls to fuck, one to have kids with and i'd keep one virgin to marry my son. I'd develop technology like electricity, metalurgy, weapons and I'll teach everything to my son because he'll become the king of the island. After some 10 generations they will have enough soldiers to expand the territory to other islands and start searching for new land. Communists and socialists will never be allowd...lol!