Jealousy is not always a bad thing. It can be an early warning system when things aren't right, but you haven't figured out what yet.
If you have examined your feelings and can't determine a cause, maybe it's just a little separation anxiety. Might I suggest you get yourself a totem.
A totem is an object that anchors certain feelings. A security blanket is a totem. The blanket itself doesn't provide security, but the feelings that are associated with it does. I suggest the next time you are in your cocoon and feeling the deep sense of love, search out an object. It can be totally random, although it should be small enough for you to carry around.
Once you have found something, meditate on it. Imagine all of the warm good loving feelings you're experiencing, flowing in it and through it. Pick it up and hold it. Be in the moment and let it soak up the good feelings.
Carry it with you, and next time you feel anxious, hold on to it and reflect on the feelings it holds.
Me: 48 - Married, straight, male
Shiela: My wife.
Suzanne: My FWB
Adam: Shiela's LDR