What to do about boyfriend's sexual dreams?

For the past few weeks, my boyfriend has been having dreams about having sex with me every night. He knows that I am waiting for marriage, and he respects my decision. When we cuddle, he doesn't feel like he's going to try to push me to do something, but he says "his downstairs gets excited." I'm not ready for sex, and he feels bad talking to me about it. Is there a way for him to control his dreams and thoughts?