Can anyone help find this hentai manga?

[kronicYo]

I vaguely remember the hentai but, I believe a wife of a rich merchant/governor found a woman sleeping in the rain. The woman seems to have amnesia but it turn out she used to be an assassin. One day the merchant/governors wife was talking to the other women and asked if she could satisfy her husband in her place since she was pregnant. I remember there being intercourse scenes at a festival and in a hotel/house. In the hotel/house scene they pick off where they left off when morning came. If it helps it seems they were in a period where vehicles were't created yet and the woman seems to have been dressed in a kimono.