What Causes Brown Discharge And Itching In Vagina After Sex?

Recently I went for HPV test due to irritation in my vaginal area and the result came out negative. I had my period abt 2 weeks ago n I didnt have intercourse with my fiancee until today. We practice safe sex all the time. After the intercourse, I wiped my vagina with tissues and found brown discharge...since then, I feel itchy in my vaginal area... Please advise.