I mean for monogamous people, it's not necessarily that feeling attraction to others is bad or cheating. It's about whether you choose to invest energy developing a sexual and/or romantic relationship with someone else.

People have crushes all the time. That's natural and normal. But you can choose to feed the crush and make it stronger and put yourself in temptation's way to cheat, or you can choose not to feed it and instead invest more time in your existing relationship.

I'm open to polyamory but right now my husband and I are monogamous. And I could see myself staying monogamous. That does not mean I don't have feelings for other people sometimes. It just means I don't invest energy into those attractions.

People who cheat always like to say "it just happened" as if they had no choice. But I've noticed with the times I'm attracted to others, that I could choose whether to find excuses to spend extra alone time with the person I'm attracted to, that I could choose whether to express my attraction, that I could choose every single step that would lead me down the path of wanting to cheat, vs having a pleasant but idle fantasy.

Yes some monogamous people think having any stray feelings of attraction is bad. But that's not inherent to monogamy, plenty of monogamous people only care if you act on your attraction.