There is no evidence that JC even had a close relationship with MM in the NT and you know it
John Shelby Spong thinks differently, and he has made a case for just that. And really, I think it is just as credible as the evidence with Jesus being gay.
I mean, one of his arguments is that Mary seemingly thought that she had a right to the body (after he died) of Jesus. This would suggest, according to him, that they were indeed married. And if we are taking writings outside of the NT (such as with the Secret Gospel), we can look at various Gnostic Texts that support an idea. I'm not saying I buy it, but that I think it is just as probable as Jesus being gay.
Not would even Ehrman suggest that Q did not exist
He does state that it is a hypothetical document, and that there are other options. The majority of scholars do accept the Q hypothesis. However, I do not think it is a must.