Let’s face it, Sherlock, you’d make a terrible best man. So John would have to ask Lestrade and then you’d get all pissy and ruin the reception if not the wedding (although it would certainly be fun for all if you were drugged and joined in on Thriller…).
Okay, so I was recently in a brief discussion with someone who was worrying about the fact that Mary Morteson should be turning up soon in the series and that would end up with John Watson getting married and moving out of 221B and I was agreeing it was inevitable when someone else pointed out that *John marries BEFORE The Final Problem* in Sir Arthur Conan Doyle’s Canon *and she dies BEFORE The Empty House.*
I went back and re-re-read the stories and sure enough, John has a very fast courtship and a rather brief marriage and, like a good Victorian wife in so many stories, she dies as soon as she becomes inconvenient. So either Mofftiss and company are dropping Mary entirely from their series or she might be making her entire appearance off-camera in the intervening period before Sherlock returns. Personally, I’d love to see Sherlock’s reaction to John explaining that he’d gotten married.
Of course, the fanfic writers have been having Sherlock hook up with Irene Adler in the intervening period and producing a little Hamish in tow, so I suppose it’s only fair for John to get some downtime action — and at least he knows to use protection… The really scary fanfic have Moriarty reproducing (usually with Adler).