Dear lady, There are many possibilities in such a case, none too serious. Firstly, pls try to recollect if this bleeding was cyclical and coincidentally post coital. After a partial hysterectomy, with ovaries still insitu, the remaining endometrium would still menstruate and bleeding wont be as much as previous periods. This bleeding may get absorbed naturally, and leak out postcoitally. Other possibility could be a vigourous penetration, which causes mild bleeding postcoitally, because after partial hysterectomy, the vaginal orifice also to become smaller in size and bleed post hysteectomy. Also, pls visit a gynaecologist anc get yourself screened for any other serious issue like endometriosis, adenomyosis, cervicitis, endometritis, cancer etc. A pap smear would serve good purpose. Get well soon!