Question about marital status in WP extension form

[Lady_Ashka]

I have a question about formalities: the application to extend stay in Canada as a foreign worker has a marital status question, and I'm not sure what I did was right

I moved in with my Canadian boyfriend in September 2014, and I thought that common law becomes official after we've lived together for a year, so in my application to extend my WP in July 2015 (and in the one I submitted in October 2014 for my first WP) I did not put in any information about it, because I though we were not common law until September 2015. But recently someone raised my doubts as to whether I should've given that information immediately after I moved in with him? I am confused now and worry that that might somehow influence our application for PR for me (he will sponsor me). I will be applying for another extension of WP this summer and I wonder, should I, apart from of course now putting in that I am in a common law relationship with a Canadian, also include some kind of letter explaining why I didn't mention it earlier? Will that suffice? Or maybe I was right in understanding that common law starts after a year of cohabitation? Help