I spent some time working on this sort of issue in the spring, and i think i significantly shortened the time the longing and jalousy lasted.
I would sit and say, repeatedly, things like "It is ok that she is with someone else instead of me", letting go into that. Also, saying, after some examination, sitting and saying "i want things right now to be other than they are right now", and feeling the absurdity of that, and the pain of it, and letting go.
Also, noticing the moments of sensory peace and clarity when the introvert self-abuse lifts for a while. Tonglen practice can be good for this, and if fitted to the situation, also great for dealing with these sorts of emotions. What i did for tonglen was basically this:
http://news.bbc.co.uk/dna/place-lancashire/plain/A1045784in the middle bit "Inhale deeply, drawing the imaginary smoke into your very core, Let it dissolve the seed of ego-clinging identity, which is trying to protect itself from the negativity.", you should (according to me), when the "smoke" and the "core" "touch", let go of attending to whatever you regard as your core, and let go of attending to the smoke, surrendering any distinction or distance between them. This will tend to produce a moment of (conceptual)mind -blowing clarity where you forget everything but the pure sensory presence right here, wow! When you can think again, do the breathing out thing.