Remove the lines:
AddType php5-cgi …
AddHandler php5-cgi …
Those two lines that were an attempt to tell the web server to treat .htm, .html and .shtml as if they were PHP scripts.
So if they are not actually PHP scripts, remove both of those lines. Once you have done so:
.php files will run PHP 5 as CGI (no SSI!)
.htm, .html will be plain HTML documents (no PHP code or SSI)
.shtml will be HTML documents parsed for SSI (no PHP code)
Which is the default setup. You have not provided enough information to determine if you need something different.