I think that it is cute for a 1st grader to be in love and that it is perfectly normal like margypops said the sleeping with thing is probably just because that you and your husband love each other plus you two
sleep together so he wants her to
sleep with hi. Or he just wants to be close to her, for many people in love want to be near the person they love. Like I said it is perfectly normal just don't make a big deal out of it wont be a problem.