adding https is breaking my site

Hi, I have added SSL on and They are both using the Avada theme. Https did not break, but it keeps breaking I added https using code in htaccess file. I also tried to use really simple ssl which did not work on both websites (it broke both sites). I tried using itheme security plugin and it also partly broke the site on The page I used it on broke and the site kept loggin me out like all the time. Is there anything I can do to get https to work without it breaking the site. Is there anything that can be done?
Cheers, Ingie