Here is the solution in case anyone is wondering:
<?php
if( have_rows('slide') ):
$i = 1;
while ( have_rows('slide') ) :
the_row();
// Check if we've reached our limit, and if so... start again!
if ( $i > 3 )
{
$i = 1;
}
?>
<div class="slide num-<?php echo $i; ?>">
<p><?php the_sub_field('text1'); ?></p>
<p><?php the_sub_field('text2'); ?></p>
</div>
<?php
$i++;
endwhile;
endif;
?>