My wife and I just recently came over from a Mono to a Poly relationship. We pretty much already had the "we can mess around with other people as long as it doesn't get too serious without each other involved" rule before this since a few months before we got married. But once she realized her relationship with one of our good friends was starting to become more, we had a talk about it and decided that this is what we want. We know it will take a bit of work and a fuckton of communication. Given how our relationship has been so far ( awesome! ) I have high hopes for us, and while I may have anxieties ( Mostly just needing to follow a lot of the advise on this board and work on myself and get out there ) I know one absolute truth. My wife loves me, and I love her dearly. Sorry for the longer intro, but let me try to tackle the questions
1) I don't see how this is going to work if he has a free pass to go find other women, but gets jealous over you. You may or may not actually want to see other people, but you should by all rights have the option. Especially since HE is the one who is wanting to go forward with this.
2) I would sure hope you two would still have a relationship, the idea is that he want's to love you as well as other people. I'm pretty new to all of this myself but I don't think there is any sort of living arrangement protocol, but if you already live with your boyfriend, that shouldn't change. If her moving in comes up later, you can cross that bridge when you get to it. But that should be something further out in the future to make sure you can actually live together without killing eachother.
3) That is polygamy. Polyamory is a bit more open on who is seeing who and what the extent of their relationship is. I know a few couple's who are married and have their boyfriends and girlfriends.
I would encourage just looking through the forums here, Here are a few links a friend of mine gave me to read through.
People on here seem pretty good to talk to, but if I can answer anything else I'll be glad to try my hand since we both seem to be in similar stages of newbiness in regards to this.
I wanted to make a quick clarification of Poly vs Cheating. In my view your relationship is what you make of it. And thus the bar for cheating changes with each relationship. Cheating in my mind is sneaking around outside of the boundaries of your own relationship. In an ideal relationship, if you are open about your other lovers, than it should not be a problem, you agree'd that you could have other loves. It is within the boundaries of your relationship.