I heard the discussion between you and Lexy just some minuts ago in the living room.
In just 3 days you understand who Em & Sid are: they are antisocial, they never invite a friend, they do not have a party, they do not talk to each other and they spend whole days in different rooms (they cannot anymore) attached to the computer and cell phone .
They were also rude to you and welcomed you as usurpers of "their" house knowing full well that it was Alex's decision.
Em & Sid did not have sex (maybe Em did it outside the home) for 48 days! It seems possible to them at their age ?
You must be patient. Ciao from Italy