Saw this in a other section; thought it might help you. Proof of common-law relationship:
Provide documentation from 2 of the 3 sets of options for evidence of current cohabitation (for a minimum of 12 months):
-Joint ownership of residential property or joint residential leases or joint rental agreements listing both the sponsor and the principal applicant (Minimum 1 document)
-Proof of joint utilities accounts (Electricity, Gas, Telephone) (Minimum 1 Document)
-Important documents for you and your sponsor showing the same address, such as copies of government issued identification documents: driver's licenses, insurance policies, etc. (Minimum 1 Document)
If you can prove the opposite for the three years you were together, it might help in your claims. Maybe utility bills still in your parent's names throughout the period, important documents showing you and your boyfriend at different addresses over the same period, etc.
Yes, maybe that can help to prove our claim. We dont have any residential leases, utility bills was under my parents name and all his ids was address in their home.