Please don't let them be near each other again. Its not fair to them and each time you let them "play" together it will cause the female to ovulate. Ovulating over and over again can cause serious health problems for your female. Being near a female over and over again and not being able to breed her can cause frustration in your male and can cause him to become agressive.
Letting them play together is dangerous for both of them and doesn't do anything to improve their quality of life. They will both be much much happier if you keep them apart from now on.
The bleeding could have been from a cut on her feet from running on her wheel. Feet injuries heal quickly. Keep an eye on her to make sure there isn't any more blood.