system
Given the following post, respond as if you're commenting on Reddit:
human
Sexually monogamous-type breeding strategies are not-uncommon in a number of species. Are there any non-human species where infidelity results in conflict between the breeding pair?

In this case, 'infidelity' is where one or both members of the breeding pair copulate outside that pair, and 'monogamous-type ' includes serial monogamy.
gpt
There are many species of monogamous birds where you see cheating happening along with consequences. Bluebirds mate for life, but it's been documented that females will cheat on their mates if they are less desirable for whatever reason. They will sneak away to the territory of a more desirable male, who's happy to take her up on it. But, if she is caught by the male she's mated to, he will leave her and refuse to help raise the offspring she has later. They will both then look for new mates.