What Causes Bleeding After Sex When Having Paraguard?

Hi, I have had the paraguard for 9 years. My menstrual cycle was 7 days late but it came fully for 4 days. I have never had issues with the paraguard. I do have unprotected sex with my husband. We had sex yesterday and there was blood afterwards on him and later on in the day I wiped I saw light blood on the tissue...Please help