My husband gets headaches after sex, when he finishes, what could be the cause of the headache?

Can be common: Both men and women can experience headaches with sex, though it is more common in men. The vast majority of the time they are not serious, though I would recommend an evaluation with his doctor to rule out more serious causes.

Exertional Headache: Headaches occurring during or after sexual intercourse are a particular type of "Exertional Headache" called Headache Associated With Sexual Activity or Post Coital Headaches. There are 2 types: Primary and Secondary. Primary= benign, not caused by serious disease (most are Primary). Secodary=due to serious disease, such as brain tumor. SEE: http://bit.ly/134oXr for more info. See your physician.