Pointing two domains to same IP htaccess edit

Question

I am having two domains https:www.site.com and https:www.site2.sa which is pointed to same IP.

www.site2.sa is added as addon domain.

I have put files for www.site.com in public_html and files for www.site2.com is in public_html/site2.sa

The website is in cakePHP

www.site.com is working properly. www.site2.com is showing 500 internal server error

Should I change something in database? or should i do something in .htaccess?

My .htaccess in public_html is

# BEGIN GD-SSL
<IfModule mod_rewrite.c>
Options +FollowSymLinks
RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteCond %{HTTP_USER_AGENT} ^(.+)$
RewriteCond %{SERVER_NAME} ^site\.com$ [OR]
RewriteCond %{SERVER_NAME} ^www\.site\.com$
RewriteRule .* https://%{SERVER_NAME}%{REQUEST_URI} [R=301,L]
Header add Strict-Transport-Security "max-age=300"
</IfModule>
# END GD-SSL

<IfModule mod_rewrite.c>
RewriteEngine on
RewriteRule    ^$    webroot/    [L]
RewriteRule    (.*) webroot/$1    [L]
</IfModule>

Answer 1

This code worked for me

 <IfModule mod_rewrite.c>
 RewriteEngine on
 RewriteCond %{HTTP_HOST} ^site\.com [NC] 
 RewriteRule    ^(.*)$ webroot/$1 [L]

 RewriteCond %{HTTP_HOST} ^site2\.sa [NC]
 RewriteRule    ^(.*)$ site2.sa/webroot/$1 [L]
</IfModule>

but images from webroot are not loading now. some one have the solution?