Mommal, I appreciate your response and suggestions. You're right that I may need to "spin" things a bit to DH. I feel like that's unfortunate; of all the people I should be able to be honest with, my partner is #1. But you may be right that it may help to spin things a bit.
DH already does a good bit with DS on his own...he gets up with DS one day each weekend when it's my turn to sleep in. He watches DS when I have to work on the weekend (tonight, for example). I would say in general, they have a great relationship. And DS will cuddle up a bit to DH when I'm not there. When I am there, though, he usually prefers me. (It does go back and forth a bit, but usually he prefers me, at least for cuddling/affection). DH and DS have a wonderful time playing together. DH is really great about playing on a toddler's level and never gets tired of playing He's also really, really good at distraction--better than I am, really. So I don't see a deficiency in their relationship. DS adores his Daddy. Although sometimes DH is less sensitive to DS' needs than I am. For example, he was willing to let DS cry at night much sooner, and for much longer, than I was. He tends to push him to eat dinner regardless of whether DS wants to eat. He wanted to make DS get a haircut even though DS was crying and a hysterical mess. He suggested that if DS isn't ready to be left alone at preschool soon, we'll just have to leave and let DS cry and DS will eventually be okay, where I feel we should either stay until he's ready to let us leave, or perhaps pull him out of preschool if he really can't make the adjustment, but either way I'm not going to force it and leave him crying. I think this has a lot to do with some harsh parenting that DH received when he was young (forced baths when he was frightened, forced potty training, etc). He sees this as normal and thinks it's a discipline issue to make DS get a haircut or take a bath regardless of whether DS wants to. He loves DS to pieces, but he isn't as sensitive/responsive as I am. He also doesn't spend nearly as much time with DS as I do--I am usually the one to get up and take care of DS in the morning before work, where DH doesn't interact in the morning other than to say a quick "goodbye" a lot of times. He also works later than I do, and I am the one to flex my schedule and find a way to come home early, go in late, take a day off here and there, etc. So all in all, I probably spend several hours more a day with DS than DH does. That might have something to do with DS' attachment to me. Plus, isn't it normal for kids to be most attached to Mommy and prefer Mommy for comfort most of the time? That's certainly what I've seen with other kids, but it really hurts DH's feelings and makes him feel slighted