What Causes Vaginal Bleeding During Bowel Moments?

I am having vaginal bleeding from past 1 week after having sex for the first timeinitially it was lesslater for around 3 days i had huge bleedingnow all that has stopped and i am facing a new problem in which i find bleeding in vagina only when i go to motionnot any other timeThere is no painit is only spotting nowthere is no pregnencyplease let me know what the problem is