My boss has it due to a malformation at the back of her throat - it literally closes up after a certain amount of time and she cannot breath. Then she wakes up, but didn't know why. She went to a sleep clinic and they discovered she stopped breathing something like 100 times a night. There can also be corrective surgery.
Alcohol consumption is a big cause of sleep apnea also.
Hope this has helped some. My H's attitude was like yours, he refused to believe me. But he snored a lot and was waking up with sort throats all the time and eventually was willing to wear those nose tapes that pull the nose open. He refused to see a doctor about the problem, however - he doesn't believe he needs a doctor for anything most of the time. The Lessons Children Learn.