Could it be
Creation by rkn?
In that one, they are divorced and get together after a luncheon, and Lois ends up pregnant.
The one I'm thinking of they had divorced because they weren't able to have kids...
This was a good read though. Thanks.
I'm thinking it probably never got archived because I'm not finding anything on the archive which means its probably too old to show up on search results on the mbs.
Update: I Found IT!!!
Sometimes Love Is All You Need 
