You can use the following syntax to exclude:
RewriteRule name_of_page_to_exclude.php - [L]
Trait ( -) is important. [L]ensures that if this rule is run, it will be processed last. Therefore, naturally, you need to place it near the top of your file .htaccessbefore the rule in your question:
RewriteEngine on
RewriteRule name_of_page_to_exclude.php - [L]
RewriteRule (.*) controller.php [L]
The documentation states the following:
- () , ( ).