Pisces are easy to be convinced of anything. What is important - to get down to business with affection. This sign is inclined to mysticism and self-sacrificing, so you can tell him, that some "higher powers" demand separation.
This sign gets along best with the strong, independent people, behind whom the gentle Pisces can feel secured, and can admire their idol, or with the wretched and miserable ones, which immediately bring Pisces a lot of worries, at the same time Pisces will be happily teaching them the right way.
If you do not belong to any of these categories, you will get rid of your Pisces pretty easy, indicating the right object for them and in the same time convincing them of your ordinariness, your limited mind and your inability to understand the "higher matters".
The only thing in any case must not be done in parting with Pisces - is trying to get them to objectively assess the situation and themselves. It may cause you an endless explanations of the relationship, which may lead to nothing, reproaches, hysterical performances and a very bad feeling for the rest of your life.