Hello, I like the idea, I think you can make it a lot shorter.
I would cut this part "but his fight for survival comes at tragic cost and he is confronted by the depths of his shame",
because 'tragic cost' is vague, and 'confronted by the depths of his shame' is not a clear visual element of the plot (it seems more an explanation of the inner conflict).
Then ask yourself what is the real element that put the story in motion: the adultery, the meeting with the french couple, or the first violent act of the couple. I think the violence of the couple is not clear enough, what do you mean exacly? Maybe the adultery could be just back story?
I wonder if the nationality of the couple is really foundamental, in the logline. The fact that they are french doesn't seem related to any other element in the logline. Maybe what is interesting is that the farmer is african native and the couple is caucasian, this could be the framework for a kind of sadomasochistic relation.
Finally, I miss a clear active goal for the main character. What is his goal? To win back the love of his wife? To punish her? To punish himself? The goal can change at the very end of the movie in the moment of the self revelation and this can be a very effective moment.
Every word counts, so ask yourself why each word is there. To understand if a word is necessary, ask yourself if it is related to other elements- if not it's just a detail that should be avoided. I like the word "proud" for exemple because it's the character's flow and it relates to the adultery and, I imagine, to the final fight agaist the French couple (the main character's flaw becomes his strenght).
Good luck.