It's NOT for Everyone!
I will never understand people who introduce polyamory into unstable relationships. I've been there, and it doesn't work if there isn't a strong base in which to build from. If you can't trust your partner's intentions, that isn't going to get better by allowing them to be intimate with someone else. If you're prone to ridiculous amounts of jealousy, being poly is probably not something you want to pursue. Would you go iceskating on a cracked pond? Drive your car cross-country with a flat tire? Play with matches in a hay shed? Probably not. So, don't be stupid, people.