It's been a little over a year since my wife and I have had vaginal sex.  But, that's for more than one reason.
For me, I like denial.  When she has a regular bf, as she does now, I like giving him complete ownership of her pussy.  He's a well hung, young stud and he practically lives with us.  I do lots of clean up on both of them and we will do an occasional DP where I am allowed to enter her butt.  Or, she will suck my dick a little while he is fucking her, because she does like hosting two cocks at one time
However, I love knowing that my wife's pussy has only felt her bf's much larger cock for a little over a year now, instead of mine.  I also love knowing that she has been carrying only his sperm inside of her, instead of mine, for a little over a year, too.