What Causes Bad Odor Brown Discharge After Intercourse?

I stopped weaning my baby last month. I had a normal period that lasted 6 days. 2 days later after having sex I noticed a brown discharge with an odd smell, like the blood following having a baby. It has continued for seven days. After having sex again dark brown blood came out. It has an earthy smell but only seems to discharge after sex or when I put a tampon in. Other times no discharge.