monogynist
/mɑnˈɒɡaɪnɪst/Definitions
1. noun
A person who advocates or believes in monogyny, or the practice of having only one mate or spouse.
“The social scientist was a vocal monogynist, arguing that polygamy had negative effects on family dynamics.”
2. adjective
Relating to or advocating monogyny.
“The monogynist marriage counselor helped couples work through issues related to infidelity.”