I've been in a septagonal polyamorous relationship for almost a month now with my fiance and five other people who I've been really close to-- some more physically than others-- for several years now. That pales in comparison to the experience already present in the dialog here, but I've been feeling in a similar way.
My fiance and I have gone through ups and downs in our monogamous relationship over the years. We've had many problems from simply wanting more time together, a change in our routine, or more effort in how we each sustain the relationship (i.e. emotional involvement, school/work). We have several people in our lives that we've tried to use as examples or archetypes. For instance, her parents (like us) are highschool sweethearts who have tried swinging. My aunt and uncle are hippies (enough said). We initially came to this forum also looking for advice and insight, and I think out of all of the sources we've examined, it's my father who gave me the fittest solution.
When it comes to how you handle a relationship-- who does more, or what's expected of each person-- there is no right answer. You do what you feel your partner needs. If you need something you aren't getting, ask for it. If the answer is no, and you can't deal with that, then get out.
There isn't much more you can do, unless you're like me and you enjoy intensive masochism and self inflicted misery :\ Don't be like me lol.