I usually associate "lifestyle" with swinging. The swingers seem to have claimed that word for themselves.
I find swinging and poly to be very different forms of the same thing, non-manogomy. Swingers seem to have many rules such as, same room only, soft swap only. No playing on the first date. Girl-girl only. Although many do like to establish close friendships with those they play with they tend to keep the emotional connections at arms length. Poly people seem to have less rules, but it is more about the emotional connection and less about sex. Anyways, that's my take on it, but I am still pretty new to the whole thing.
As for causing a shit-storm by jumping into something you're not ready for in your relationship, I'm not sure that's a good idea. Swingers call that "drama" and avoid it as much as possible. I've heard of a couple instances where couples think they're ready for the lifestyle stuff, but they're not. It's usually unpleasant for themselves and those they play with too.