"Wow, several types of birds are monogamous."
It's not just birds, but many mammals as well...
"We as humans are programmed to pass on our genes to as many mates as possible- sticking with one mate is a direct violation of our natural instincts."
First of all, humans lack instinct...Maybe if you replaced "instinct" with "hormones" it'd work out...Second, if this were the case, then why do such species as foxes, for example, mate for life?
And the main reason for spouses cheating on each other is boredom of each other, which as far as science knows, is a feeling only humans get...