This discussion always annoys the heck out of me...
If you really truly live together, you will be getting mail at the same address. Period. You don't even need a lease or a joint utility bill. Just something like a bank statement, credit card bill, university marks, anything. You produce something dated a year ago in your name, he/she produces something in his/her name dated a year ago. Bingo, common law status acheived. If you're not getting mail there, you don't really live there. Whatever reason you have to get your all of your mail sent somewhere else indicates a lack of true "common law" status.
have resided together as husband and wife continuously for at least one year immediately preceding the application
(from CFAO 19-41) (emphasis mine)
When I was on SLT there was a bunch of guys trying to prove common law status, but only after they found out that they won't have to pay R&Q. You're asked your marital status on enrollment, if you answer "single" then you find out there is financial benefit to being common law, then change your mind...come on! There were guys who were "common law" in university, joined the CF, girlfriend moved back in with her parents and they still wanted/expected the free R&Q.
Common law status is the equivalent of married. It is not a convenient relationship for some financial benefit. Here's a question when deciding your status - who gets your Supplementary Death Benefit, SISIP, and pension when/if you die? If the answer is (at least in part) "my spouse" then go ahead. If you can't stomach the idea of him/her being your beneficiary, then you're not really common law, you're room-mates.
ive been helping her pay rent for a few years.
That's not common law.