I figured out that tags need to be added outside the for loop, and each field can be wrapped in a separate for loop. Works as expected now.
<h3>
<b>
{% for therapist_full_title in item %} {{ therapist_full_title.therapist_name }}
{% endfor %}
</b>
{% for therapist_full_title in item %}
{{ therapist_full_title.therapist_accreditation }}
{% endfor %}
</h3>
(edit: code format was stripping out one of the fields)