If you develop feelings for someone else, that doesn’t mean you automatically have to abandon your existing life for the new potential love
You get the chance to build a “village” in your home, based on love and affection (hopefully without limits!) and don’t have to limit physical affection or emotional intimacy with any of the consenting adults involved in the mix (although you can and it’ll add a lovely mix of drama and stress to your household)
You’ll be encouraged by most of the poly community to adapt your own standards of ANY kind to your love life (rather than judged by the traditional community for not abiding by traditional values and behaviors)
Sometimes you end up like folk @Rainbow_Kitten7 with crazy, sexy adventures ALL. THE. TIME.
Adding this at the prompting of @kahana: This may or may not be seen as a benefit, BUT a lack of open communication will nine times out of ten destroy a non monogamous relationship. You’re forced to either step up or step down, so to speak. If YOU’RE the one that typically puts in all the effort, you’ll probably appreciate that your partner can no longer slack off in this respect!
Real Benefits of Monogamy
You don’t have to come up with your own way of living and loving, but only need to modify it slightly as to what works best for you (i.e. having a child, not having children, etc).
Society will judge you less, especially if you go more traditional (marriage, children, etc.)
You’ll have less chance, as a man, of raising another man’s child and/or paying child support (don’t know that I love this one, but this was one suggested to me by someone else and I guess it IS a benefit!)
You don’t have to explain yourself to every new person you meet with a 15 min TED talk about how your romantic life works