help me find a story....

I read it a year or so ago, but I'm afraid I don't know how old it is.

Anyway, it involved two couples who were friends. One couple can't get pregnant, and the difficulty is on the man's side. And so they get the man from the other couple to donate in a natural way. They try to make it only minimally erotic, but as time goes on it and they have to try again and again, it gets more and more erotic, in spite of themselves.

By any chance does that ring any bells? I used the search function for pregnancy and even impregnation, but that didn't narrow it down enough to be useful.

I realize this is not much to go on, and there's only a small chance that someone here remembers this one and knows how to find it.

But thanks in advance if, by any chance, it can be located.

Do you happen to remember from whose point of view is the story told? The Husband, his Wife or the Donor's?

EDIT:
Might it be this one? http://www.literotica.com/stories/memberpage.php?uid=1541499&page=submissions

Did you try the 'sperm donor' tag?

http://tags.literotica.com/sperm donor

Still can't find it. But thanks for the help.