That sounds familiar.  I think I know the story, but I don’t remember the name of it and I don’t have it in my favorites.  If I’m wrong then I’m wrong, but if I’m right then here are the few details I know of the story I’m thinking of.
I believe Inuyasha goes to future to be with Kagome.  Years later in modern time Sesshomaru sees a woman walking with a child with white hair, but the woman’s not Kagome.  Turns out Inuyasha left Kagome and  is married to another woman.  I think he became a movie producer or director or writer.  Obviously Sesshomaru and Kagome got together.  I think he helped her get over the rejection she was feeling of being seen wanting again after going through it with Kikyou in the past.
Edit: well Fubuki posted the story I was thinking of. 
