I Have Not Done Cocaine Since Late November 2016. Now

I have not done cocaine since late November 2016. Now in mid January I had to take a urine drug test. I almost failed because the indicator line for cocaine was faint. My boyfriend does cocaine daily and he cums inside me almost daily when we have sex. Could i have nearly failed due to the small amounts of cocaine in his sperm? I honestly don't see any other explanations on why that indicator line on my drug test was so faint. I was embarrassed when the person who gave me the test was doubtful. What if they do a hair folicle drug test as well in the future and i fail when im really not using the drug at all. Please do more research and get back to me. Because that line was so faint i will be getting random testings. Im cool with that but its not fair for me to fail when im truly clean. Please help.