There are two kinds of Queen.

1. Queen regnant. http://en.wikipedia.org/wiki/Queen_regnant

2. Queen consort. http://en.wikipedia.org/wiki/Queen_consort

(OK, there are a couple more, queen dowager and queen mother, but I don't think they are relevant to this discussion).

I would expect the wife of a queen regnant to be a queen consort.

Are royals obliged to get married by the Church of England (who are legally barred from performing gay marriages, thus precluding the scenario in your question)?