I had light spotting 24 hours after sex for a day, went away then spotting re-appeared 1 week later. there was no ejaculation what could be wrong?

See answer : Mild, self-limiting, periodic spotting of blood after sex is common. Often just related to the intensity, frequency, and/or duration of sexual activity causing irritation of the vaginal lining or cervix, especially if lubrication inadequate. Sometimes related to underlying inflammation of vagina/cervix, polpys, fibroids, etc. If persists, recommend manual/speculum gyne exam and PAP smear.