What Can Be The Reason For Fishy Smell After Sex?

Hi! I had a partial Hysterectomy on Nov 2009-- I notice that now I have a fishy smell sometime after sex and even regularly-- I was wondering if this can be related to not having a monthly period? I am extremely clean and I have asked my doctor about it, I also get tested regularly and everything seems to be fine. This is affecting my self esteem and my sexual life. What can I do?