Thanks for using healthcare magic forum.
I have gone through your available history.
You might have developed minor vaginal abrasion or tear which has not healed up properly. Because of this, you have bleeding while sex. But You should also rule out any cervical pathology.
You should consult your Gynecologist for detailed evaluation and management. Doctor will also rule out cervical infection
You should also avoid sex until you heal completely.
I hope You will be fine soon and regain sex life quickly.