Do I tell my boyfriend about a meaningless kiss?

I was on a night out with a few of my friends. After a few drinks, me and a close guy friend started having a heartfelt conversation. In the middle the conversation, he leant in and kissed me. I was taken aback and confused. But I briefly kissed back. The kiss was for no more than a few seconds as, once I comprehended what was happening, I immediately pulled away. It did not mean anything and I feel awful. No one saw it happen and my friend told me that he’ll leave whether or not we tell anyone up to me. I fully trust that he will keep it to himself and that it did not mean anything on his side, either. My boyfriend and I have been together for 3 years and have a very happy, supportive relationship. I have no idea how or why this has happened, but I know it will never happen again. Do I tell him?

"have a very happy, supportive relationship"...means you also have trust. It'll be your conscience which dictates whether you tell your BF or not.