Having repetitive, recurring feelings of reliving disappointment over and over again is tortuous no doubt.

Was this guy a prospect after a previous heartache? I ask because you wrote that you'll never again experience a relationship. (be involved again)

How long had this mutual 'like' of one another been developing? What brings you to title the thread jealousy? Did your friend know of the shared feelings? Was she reciprocating? Did she betray you?