There’s A Lot Of Talk Of John Marrying Mary As A Way To ‘prove’ His Heterosexuality. He Felt The

There’s a lot of talk of John marrying Mary as a way to ‘prove’ his heterosexuality. He felt the need to appear ‘normal’, so he took on a normal life: wife, child, living in the suburbs. If we expand upon this a bit, I think his reaction to Mary when he finds out who she really is is telling. 

He’s not upset that she lied. He’s not upset she has a secret identity. He’s not upset that she shot Sherlock to cover up who she is. No, the thing that appears to upset him the most is that she ‘isn’t normal’. She doesn’t conform to idea of a ‘perfect’, ‘normal’ (aka, heterosexual) life. She isn’t the happy wife in the suburbs with a child, but a highly trained assassin. John chose Mary because he thought he could have a normal life with her. He chose someone who he thought was the exact opposite of Sherlock: wanting to settle down, not go on crazy, dangerous adventures.

But, even in his attempt to chose someone completely opposite to Sherlock, someone he can pretend to be straight with, he still ends up choosing someone who is similar to Sherlock in a lot of ways.