As I just replied to James' comment... At 17, I heard the same diagnosis, etc. and it went in one ear and out the other. 17 years later, I learned I was four months pregnant. I hadn't had a period in three years and the news came as a shock that lasted for weeks. Almost two years later, I heard the same news again. Five months later, I delivered our second child.

That's the long way of saying, endometriosis is not birth control, so if you two really don't want children, get a vasectomy.