Hello! Polyamorus person here. I'm non binary dating two girls at the moment. I'd say it's just because I love a lot of people. I am neurodivergent so that might be a factor but i'd say its just because love is unique for everyone. While you might be monogamous, another person might be polyamorus. Either are valid. It's just about love. Like people always say, love is love, whether its gay or straight, monogomous or polyamorus.