Yes, it's an interesting look at the dynamics of being the OP and what a relationship with a married person would entail. For example, in most cases it's not being involved with an independent, secure, emotionally stable person, but rather someone fleeing a situation they perceive negatively for something they hope will make them happier. As the OP you are not being loved for "you," but what this person hopes you can provide for them..... an alternative to what they have. And gosh, you better be BETTER or else you are going to be huge disappointment!
Ugh!!! that is a terrible burden. I have a pretty huge self-esteem, but I definitely wouldn't want that kind of pressure.
On the other hand, as a LBS, you have a nice little opportunity to make it more difficult for OP. Before the marriage is over, or during the S or D, make sure your spouse leaves with plenty of good memories. The current good ones will help change how the past is perceived... and make the OP's position even more difficult (it's a nice, safe little form of revenge).
There is no arriving, ever. It is all a continual becoming.