If you are interested in writing a story about a polyamorous relationship, by all means do so! There's no point in removing that element from it just to please someone who would object to it. Make the story you want to, and let it attract or deter people for what it is.
Edit: basically, what @gateofselidor said
Personally, I could never be in a polyamorous relationship. It's just not for me. There's nothing wrong with poly relationships and they absolutely work for some people - it's just a matter of personal preference.
Best of luck with your story!