Couples having different rooms.

Why will a couple be sleeping in separate room at night?have you ever think or thought of it, am just so surprised that some couples have initiated the 16th century method like they say the world is just revolving but not in the manner of two lovers sleeping in separate rooms in 21st century where lots of change has taken place. I know we all have what we have to say about this matter.. It happens not only in Africa but some part of Asia.
What's your opinion about this... For me I think it's an Avenue where both gender have enough space to cheat especially at night like chatting with their secrete lover or making tons of call to their male or female lover.
What's your say about this??