Somtimes LVO will send a request for proof of continuous relationship.
It means you need to collect all the material from the last date that you had sent to CIC up to the current time which can include emails, skype chat, viber, call logs, facebook and other social media.
The easiest way is to take screenshots of your phone app or computer app and post multiple images on a page in your word document.
You can google how to take screenshots with your iphone, android, mac or pc or if you know somebody who is technically good with computers.
If you had visited your spouse in Pakistan then provide your plane ticket, boarding pass and entry/exit stamp on passport.