I think the movie makes a good point of showing that whatever was going on with Mae and Earl, it wasn't love. They were drawn to each other because they were very similar. Eventually, both of them would have behaved towards each other the same way they did with other people; with contempt and indifference.
They were always dissatisfied with what they had and looked for something better; something they could never really find because it didn't exist. The truth is the dissatisfaction they felt was with themselves; that's why, however hard they tried, they would never be able to run from it or find the ideal situation. By the end of the movie Mae finally understood what had always gone wrong in her life but Earl still hadn't gotten it.
Woman, man! That's the way it should be Tarzan.
[Tarzan and his mate]