@DragonK123 Considering Watson does get married in the original story, not entirely unexpected
Further, for those who have not read the original stories, Watson meets his future wife when she brings the case to Sherlock, and had no contact with her prior to the case.
Spoiler here from the original series about her, so be warned as it is possible this MIGHT occur as part of this series.
It is well known that Sherlock and Moriarty have their "final confrontation", with each appearing to fall to their deaths. Eventually, Holmes would return after a long journey and meet back up with Watson as part of "The Adventure of the Empty House". During this period of time, Mary dies, and Watson is still in bereavement when Sherlock returns.