Issue when trying to access https://

I don’t want to have force https for the whole site

Do you want WP to use SSL all the time, or just on login?

You can do SSL for login/admin: http://codex.wordpress.org/Administration_Over_SSL

But if you want to have both http and https, it doesn’t work. WP doesn’t do ‘both’ very well.

This plugin will switch you to https all the time: http://wordpress.org/extend/plugins/wordpress-https/