Redirection of htaccess Only on Main Domain Not on Addon Domain

Hi!

I googled a lot but couldn't find solution to my problem. My problem is I have many redirections on my primary domain.

Like say for http to https , to remove page extension. for error document. to remove trailing slash etc...

But now I have a addon domain and all the redirection is working on that aswell. Plus my addon domain is ending with a url like

maindomain.com/addondomain.com

That's what am getting if I place any htaccess redirection on my primary domain. I want to remove my addon domain from my redirection.

I tried many rules but most of the time result is same or am getting 403 error page.

Please help me to resolve this issue.

Thanks