While the Cat's Away...

There are several interesting phenomena that can be observed in the case of a couple that spends a lot of time apart.

-> Even if a man masturbates that morning, his sperm count will still be higher than normal upon reuniting with his partner.

-> When the couple is reunited, the man will thrust deeper and faster when they have sex.

These are adaptive mechanisms that date back to prehistoric times, that would have ensured that, had the woman been having sex with another man, her usual partner could still assure his paternity of any future offspring. This is basically saying that the man wants to make sure he's the only possible father of any kiddies the woman may have.