You would need to build this functionality yourself.
Using the three fields you mentioned in your post you would create the HTML and link, I’m not exactly sure what you need to output from your explanation but something like
<a href="<?php the_field('affiliate'); ?>?var=<?php the_field('link'); ?>"><?php the_field('link_text'); ?></a>
I’m sure there would be more to it than that but the exact details would depend on exactly what you need to output.
