Perhaps it was his fantasy? Having sex whilst being watched by someone who was pretending to be asleep? Could explain why he needed to drug her?
No, no, no, these are not facts!
How many bedroom were in the house?
How many beds were in the house at the time?
Was one bedroom being used for storage or anything similar, therefore unusable?
Did Jeremy know beforehand (without question), did he state in previous statements that he knew CM was sleeping in another room when he was questioned about this?
It's not the norm, but what has been throughout this whole case? if Jeremy was 'open' about his sexuality, or rather not embarrassed or shy about his sexual performance in front of others...(and many people are very open, it neither makes them murderers or abusers) then he may not have realised CM was in the bed upon him entering it immediately, but recognised he was a very short time later, but carried on?
This does not make his actions to be as perverse as one makes it out to be.