Excluding the current post in reciprocal relationships

Hell Tom,

I see the issue. In this case, you will need to use the code to register the relationship and use the query args to exclude the current post from the list of posts.

add_action( 'mb_relationships_init', 'callback_function' );

function callback_function() {
    $post_id = null;
    if ( isset( $_GET['post'] ) ) {
        $post_id = intval( $_GET['post'] );
    } elseif ( isset( $_POST['post_ID'] ) ) {
        $post_id = intval( $_POST['post_ID'] );
    }

    MB_Relationships_API::register( [
        'id'         => 'post-to-post',
        'reciprocal' => true,
        'from'       => [
            'object_type' => 'post',
            'post_type'   => 'post',
            'meta_box'    => [
                'context' => 'normal',
            ],
        ],
        'to'         => [
            'object_type' => 'post',
            'post_type'   => 'post',
            'meta_box'    => [
                'context' => 'normal',
            ],
            'field'       => [
                'query_args' => [
                    'post__not_in' => [ $post_id ], // here
                ],
            ],
        ],
    ] );
}