After i had intercourse with hubby i noticed slight fresh blood and burning sensation and urge to urinate.what might be the cause?

Possible infection: It sounds like you might have a vaginal infection and possibly a urinary tract infection. Blood after intercourse may be a sign of a vaginal infection. Infections of the vagina or natural bacteria from the vagina can move upwards to your urethra and into the bladder giving you a bladder infection. This is often called post-coital uti. See your family doctor or gyn for a swab and urine eval.