I don't understand all this judgment you have about your own feelings. Twice in this thread you've said you "shouldn't" be feeling what you are feeling. Why is that? Who is telling you which feelings you are and are not supposed to have? There is no law decreed that when one engages in polyamorous relationships, one is not allowed to feel jealousy or anger or anything else. Are you not human? The more you fight or judge a feeling, the more it will keep coming up and growing in intensity until you let it be, accept how you feel, and deal with it. So, I say, be gentle with yourself and stop judging what you're going through. A break-up is a grieving process, and will have its highs and lows. When emotions rise, ride them through and they will dissipate by virtue of your simply allowing yourself to be what you are.
The world opens up... when you do.
Oh, oh, can't you see? Love is the drug for me. ~Bryan Ferry
"Love is that condition in which another person's happiness is essential to your own." ~Robert Heinlein