After a break up, you are likely to find yourself in a rebound relationship. You might take the relationship to be something like a temporary healing solution. You might also tell yourself that once the opportunity presents itself, you will go into a better and more dignified relationship.
In time, you form attachments to this person and find it harder to leave the relationship. You may get caught up in the web of this relationship and convince yourself to give it a try and to make it permanent.