No. The officer will be looking at the validity of your marriage from various angles and so the absence of a ring does not render your marriage invalid. In fact the officer will like to see evidence of the three year relationship more in pictures of both of you, with friends and family, comingling of monies and assets, utility bills in both names, addresses in your driver licenses/ID cards, rental/lease agreements and personal knowledge of yourselves. You should be able to tell how you met and what led to what. The chemistry of people who are together will show rather than jewelry or the absence of it. Good luck.
This should not be a challenge to your adjustment.
The interviewer will be more interested in a shared life than in a wedding ring,
You may attend the interview with a lawyer if you have other concerns.