Thursday, 07 June 2012
I believe this is determined by a few simple factors, namely the nature of the breakup and one's own self-esteem. If the breakup was bad, someone might be spiteful and hope that said ex is dating a loser. On the other hand, if things ended amicably, one might want to see their ex moving onto someone better and be happy for them. Another thought is that said ex at least didn't downgrade, which could stir up some self-doubts.
Of course, I think the best viewpoint is seeing an ex and yourself with people who are not necessarily better or worse, but better for each other.