There is a female researcher at the University of British Columbia that published a paper that showed that after 6 years in a monogamous relationship, men still get aroused thinking about having sex with their SO, but the SO only starts to get aroused, if at all, after sex starts.
I thought that it was the male that got the seven year itch.
The SP's should be happy that is the case, as this is a prime source of business for them.
DWB