Coyotes form monogamous pair bonds. Research suggests that these pairs often remain together for life.
Coyotes tend to live in family groups, but often hunt alone. Generally the dominant pair in a family group (the parents) are the only breeding pair, and they produce one litter per year.
Coyotes Hunting in Tandem by Matt Knoth
For more information about coyote pair bonding, check out this article by Cecilia A. Hennessey et al.