dark brown (almost black) smelly slimy discharge.

For the past 2 years, i have been getting this dark brown (almost black) smelly slimy discharge. I have gone to the doctor several times, and to a specialist only to be told that they cannot explain to me why i am getting this discharge but all my test appear normal so not to worry about it. It is now 2 years later and im still having this problem. Although the color has lightened up some to a dark brown, the odor is terrible. I need help and do not know what to do. I have this discharge frequently. Its messing up my sex life bcz i dont want anyone to smell this. Sometimes when i have had sex in the past, the discharge would be present on the man's penis. Just a few facts about me. I am 41 years old w/ reg period, not sexually active now, prone to BV, have herpes, and can only have a child through ivf. All of my pap smears have been normal since my diagnosis. Can these situations have anything to do with this dark discharge or smell? And what can i do for this problem? Pls hlp