This may sound obvious, but all of your partners have to be aware that they are dating someone polyamorous for the relationship to be polyamorous. Likewise, adding a partner to the mix is not likely to "spice up" your relationship if someone isn't getting their needs met. It takes a lot of communication, self-reflection, and emotional maturity to maintain romantic and sexual relationships with multiple partners.
In polyamory, the person your partner is dating besides you is referred to as a "metamour," or the love of your love.
Children can feel some negative emotions when a polycule breaks up and certain parental figures are no longer around.
Of course, this also happens in monogamous relationships, evidenced by more single-parent households than ever before.
In 10 years of polyamory, I can't count the number of times someone has said, "Oh I could never be polyamorous.
I'm too jealous." There's a myth that polyamorous people don't ever experience jealousy. Jealousy is the only emotion that we are allowed to use to excuse all kinds of reprehensible behavior.
The key is to share your needs and fears with your partners, and be honest about your intentions and behavior.