I have just moved in with my boyfriend. This is the first time I have ever lived with anyone. I am 20. I am really disturbed by the fact that when he wakes up in the morning, he is often erect. I feel this shows he has been thinking about other women during the night. Frankly, I believe this is disrespectful to me.

No, it isn't actually. Research shows most younger men will wake up with an erection on several mornings a week. This is a completely automatic phenomenon, and your boyfriend has no control over it at all. It certainly doesn't mean he's been thinking about other women.