I don't know about you but I love cuddling with my dogs; and its even better when you can cuddle all night in your bed with your little (or big) one while you sleep. I was one who allowed my dog to sleep with me in my bed every night until I started dog training and realized what I was allowing to happen. Allowing your dog on your bed, or any other type of furniture for that matter, boils down to the dog's state of mind.
Think of your bed or furniture as you getting a promotion at work to the corner office with the amazing view of the city skyline. If you consistently show up late, neglect turning in assignments, take 3 hour lunch breaks would your boss give you that corner office? Of course not, because your work is far below the expectations of someone deserving the promotion. Now if you think of yourself as the boss and your dog the employee does your dog deserve that corner office? If your dog is showing signs of aggression towards people and/or other dogs, has separation anxiety, resource guarding food, anxious of people or dogs, barking non-stop at the door, jumping on guests arriving, completely disregards you calling them over, jumps the fence, etc., then rewarding them with the corner office is only going to further encourage the behavior. On the other hand, your dog is easy going and listens to you, then letting your dog on the bed is okay because they are making good choices and are deserving of the promotion to the corner office.
The first step in showing leadership with your dog and changing the power dynamic is not giving your dog these luxuries. You have to teach them and show them that you are in charge and all of your furniture is owned by you, not them. You also have to teach them that your praise, affection, and those luxuries are earned. Over time, after training and withholding these luxuries, your dog's mind set will change and begin to see you as the leader. Once they start making better choices, you can slowly begin to give your dog a little more freedom and allow them to sleep on the bed sometimes. Praise and affection is earned, not freely given.