Needy!Sherlock who craves Johns approval all the time especially during sex and is always checking if he's doing it right or if John likes it. If he thinks he's done a bad Job he'll cry and beg John not to leave him promising to be better next time. John however just holds Sherlock and tells him how perfect he is... before he goes back home to Mary. Eventually it all gets too much for Sherlock and he begs John to stay with him and to not leave him anymore, John after seeing how upset Sherlock is decides that he can't put 'his' Sherlock through this anymore and decides to leave Mary. After John tries to leave to go and get his stuff Sherlock begs for John to let him go with him so he knows he'll come back. Sherlock is so distraught when John tries to leave he gives in and ends up walking into the house he shares with Mary with Sherlock clinging Sheepishly to his arm. I would love a big dramatic confrontation but with a normal Mary i.e She's not a saint but she isn't the devil either.