I think we all know of some of the attractive forces that make us want to chase after a new partner, being physically attracted to them, having similar personalities, or idealization about how good the relationship might be. While these are all good reasons to want to pursue someone, they can also be the reasons for why a relationship ends.
Take physical attractiveness as an example. We tend to see this as an extremely important factor in finding a partner, which makes sense. One usually wouldn’t date someone they aren’t physically attracted to. Unfortunately, attractive people are more likely to end their relationship to pursue new relationships. While the reason isn’t exactly clear as to why, it may be because they have more options available to them.
Another such example is individuals expectations in a relationship. Having positive expectations is of course a good thing, though having unrealistically high expectations can be a bad thing. Those with unrealistically high expectation going into a relationship can generally be ill equipped to deal with problems when they arise, favoring to ignore the problems, leading to decreased satisfaction in the relationship.
A final example of this is partners with similar attitudes. Having similar attitudes and personalities can be great for a relationship, when those attitudes are positive. However, when partners share the same negative attitudes or personality, say neuroticism , it can be a very quick downward spiral to the relationship ending.