In mammals, monogamy is rare since females nurture embryos in utero and feed them milk. Male assistance is less valuable so he can do better looking for other females. Exceptions are some carnivores where male can provide food and protection. This makes it more costly for males to search for new mates and results in their investing in current female and her offspring. Silver-backed Jackals are truly monogamous.
Males feed young.
Wolves and hyenas, dominant female inhibits other females from breeding. Usually mates only with dominant male. Monogamy is proving to be less than absolute. These are not all due to forced copulations, but often times involve active solicitation by the females. Don't know of any cases where this appears to be a primary factor, but it may tip the balance in favor of this kind of system.