Spotting one week after ovulation

Angela

Every month accept for one since last December I have spotted lightly exactly a week after ovulation. My husband and I have been try for two and a half years. At first I thought this was implantation bleeding but then it started happening every month. Any one know what it could be. The doc said that it’s from ovulation but it’s always a week after I ovulate so I don’t understand how that could be.