It's a completed story. I don't remember the beginning but Sesshoumaru and Kagome are mates. Then some lord gifts Sesshoumaru with a full demon woman concubine and he accepts out of pride - their mating goes downhill from there. Kagome gets extremely jealous of the concubine.. whose name begins with an "N"? Eventually their marriage falls apart and Sesshoumaru "unmates" her and makes the concubine his "official" mate. Kagome is pregnant with twins and lives with Sesshoumaru's old friend... who has a harem. I know the ending is the concubine has Sess's son and dies, and Sess and Kagome get back together till she dies trying to bear him a son (after 6 daughters)?

I really loved this story :[.

I think you're talking about The Western Bond by Aeries.

dokuga.com/spark/story/2609/1

=)