Share 'My girlfriends necklace'

I have a question about who is responsible for suffering...and the answer I know is always "me". But I need help getting there. And can't think of any way to get there but via a story.... Let us say.... A guy (Joe) has a girlfriend (Sue). They are not married and both date other people, that is not a big deal. They deal with a little jealousy and insecurity, but are committed to dating other p…