My DS has always been very attached. As a single WAHM, it hasn't been too much of a problem since I don't really need to be away from him anyways, but there were times that it got pretty frustrating. When he was probably about 10 months old, I had to go in for a breast exam to get a lump checked out. The nurse held him right beside me during the exam. He was okay at first, because he was right by me, but then the moment the doctor touched my breast, DS flipped out and started trying to get to me. When the nurse wouldn't let him go, he grabbed her face as hard as he could and screamed at her, almost growling. First sign of a temper I ever saw on that kid. He was nearly unconsolable by the time it was over. I had to nurse him to sleep before we could leave. I was supposed to go back afterwards for an ultrasound on the mass, and never went because I was terrified about how DS would handle it. However, I will be going back in very soon. At 15 months, matters are much, much better. In such a short time, he's become so much more independent. Though I leave the door open so he can come in here and there, I take most of my showers alone now. He naps in the family bed alone. As long as his needs are met, I can tell him "Sweetie, I'm going in the work room for a few minutes. I'll be back," and he'll be just fine. I've left him in the waiting room at several doctor's appointments with a friend, and it's been tearless. He's thrilled when I come back, but he's okay with me leaving. I've met his needs as promptly as possible from birth with the hope that eventually he would see that when he needs me I'll be there and he would be become comfortable enough in that knowledge to start exploring his world on his own, and ya know what, that time has come. We still cosleep, I've never let him CIO, we still breastfeed, and he is not a clingy little monster. He's a confident and independent toddler. There were definitely times I had my doubts about the direction we were going, but it's all turned out okay.
It gets better. Separation anxiety is pretty normal at that age, but it doesn't last forever. If you don't feel comfortable getting a crib and having him CIO, you don't have to. It's not a cure-all. The most I'd do at this point is probably put extra focus on helping him bond with Daddy. Being more attached to the primary caregiver is also very normal, but I can definitely see how that could be hurtful to your DH. I haven't had to deal with that bit myself, but I've heard that sort of situation tends to get better right along with the separation anxiety.