A couple of months ago my husband experienced some blood in his underwear, he then had a pain and a clot seemed to come out. Bleeding stopped. It happened again and this time there was no pain, he had blood in his underwear when he woke up. We have not had sexual intercourse for over 2 yrs. so it is not from sexual activity. What would cause it to happen 2x's? Why periodically in over a couple months?

Summarized question: What causes recurring nocturnal bleeding?