Here's an example (taken from real life, names changed blah blah blah):
Years ago, I worked with this guy we'll call TT. TT was in his early 40s and lived with his mother and sister out on the island. While I don't believe that pot is physically addictive, he was definite proof that there is an addictive quality to it: he'd smoke a joint in the morning, one as he walked to work from the train, one at lunch, one on his walk back to the train and one in the evening. He was also obsessed with sports. By "obsessed" I mean that he followed teams and decorated the walls of his office with scores and tickets stubs. During the weekends he'd travel to various areas/stadiums to attend games, mostly staying overnight in his car in the parking lot.**
Many years earlier, shortly before graduating from college, he and his girlfriend traveled to Florida (I think Orlando) for Spring Break. Now, March is also time for the NCAA Basketball Playoffs - this was before March Madness without the the television frenzy that we now have. TT wanted to order pizza and listen to the game in the hotel room, his girlfriend had other ideas, particularly since sports really wasn't her thing. Unsurprisingly they broke up.
When I met TT he was still obsessed with this woman. He informed me that 15 years after the break-up his college had beaten her college in the NCAA finals and she must be just writhing with embarrassment. You'll have to imagine his shock when I suggested that she was completely unaware of this (based both on her not caring about NCAA basketball when they were dating and on the likelihood that she'd moved on with her life). It was a further shock to him when I told him that it was probably not the best idea to celebrate their "25th anniversary" by buying two tickets to a hockey game and hand-delivering her a card with one ticket inside (this after she'd asked him to stop sending cards). My guess was that she was just tossing the cards in the garbage without opening them.
Long anecdote short, after this long, he should have moved on from this relationship. Sadly, it still informed who he was and how he related to the world. My point? Often I find that I, too, have held on to a relationship (with a relative, former friend, employer, colleague, whom ever) for far too long, finding reasons not to move on from what happened and thinking about ways in which my current actions have somehow affected them long after we ended.
They've forgotten me, right? Isn't the best sign that I've moved on to forget them? Decluttering those memories can only be healthy.
** TT invited me to come with him to an Oriole's game at the newly built Camden Yards; I passed.