One of the fundamental exercises in building relationships involves figuring out, exactly, what it is each person needs from a relationship. How much time? How much affection? How much sex? What sort of shared activities? How many shared activities? And so on.
And sort what you need from what you want. Needs are those things absolutely necessary to say one is in a relationship and it's working. Wants are those things that would be really nice to have, though aren't absolutely essential.
Once each person has figured out what they need and want, then you can negotiate how to meet all the needs and as many of the wants as possible.
Remember that achieving balance doesn't necessarily mean that equal amounts of time, attention, or affection are doled out. Balance is achieved when each person gets what they need and enough of what they what for the relationship to be satisfying.
When speaking of various forms of non-monogamy...it ain't poly if you're just fucking around.
While polyamory, open relationships, and swinging are all distinctly different approaches to non-monogamy, they are not mutually exlusive. Folks can, and some do, engage in more than one of them at a time--and it's all good.