Hi minime,
I was in the same situation a couple of months ago and gosh I got so scared but all is well now Thank God. I think in our situation we concentrated on proving that our relationship was genuine and did not concentrate on cohabitation evidence, though we had submitted little evidence of cohabitation. My partner and I decided to provide new evidence even some of the evidence that we had already provided. The rational for this was.......just in case cic lost that evidence. Additionally we thought it would not harm my application should they receive duplicates. I moved to Canada from Europe to join my partner thererfore I was not on his lease, however we moved to a new add in July 2013 and both names were on the lease. I wrote a letter to cic about this. I sent doctors letters, I was a bit over the top, I sent my bank statements from the time I moved to Canada till November 2013, highlighting shared expenses etc. Additionally all bills were in my partners name but indicated on the bank statements that I paid for some of them. Sent individual letters showing same address. Notorized a common law declaration for the 2nd time, got letters from 2 friends, 4 family members, my church pastor and 2 work colleague's notorized to confirm our relationship, bills in my partners name showing same address and that i pay for them, tax returns, child tax returns more photos. of us and our baby. Photos of our baby's first birthday together, photos of us in restaurants with our baby at different stages of her life, she is almost 2 years now. So we included family photos of us together in our home and different public places. Evidence of buying furniture together, letters from the bank with both our names, credit card statements with both our names. Explained our future plans here in Canada in the letter, not sure if it was important but we did include.This is what I can remember at the top of my head. I thought they wil, get back to us in 11 minths or so but Thank God it was only 5 weeks. Hope this helps.