get_user_meta destroys backslashes!!!

Hello friends!

I have a form in my wordpress environment

<form action="" method="post">
            <textarea name="message"></textarea>
            <input type="submit" value="Post" />
</form>

After submitting the form, I receive and store the data with

$all_data_ever_posted = get_user_meta( $user_id, 'all_data_ever_posted', true );
if($_POST["message"]) {
            $all_data_ever_posted[] = stripslashes($_POST["message"]);
            update_user_meta($user_id, 'all_data_ever_posted', $all_data_ever_posted);
}

When I enter normal things without backslashes and so on, everything is fine and the thing is stored in the database.
But if I enter e.g. “\test”, the $_POST is rightly transported and put into the array. But when i update the user_meta and get_user_meta the next time, the “\” is gone!

What am i doing wrong?
Please tell me the correct way to store special characters in the custom fields of wordpress.