What Causes Swelling In Penis After Intercourse?

Hi, last night my husband and I had sex, everything was good. This morning my husband had a bloody vein-looking discharge from his penis. Was a bit painful after 1st urination, then ok.This afternoon he said he was a little swollen but fine, he has no bad habits and we are absolutely monagomous. He has Type 2 Diabetes, high choloresterol and high blood pressure 46 years old. He has had recent blood tests and had his prosterate checked.