I have a six month old lab mix (not sure what with maybe akita or some kind of eskimo dog) that we adopted from the humane society at 4 months old. I also have a two and a half month old terrier mix that we adopted about a week ago. Obi, our lab mix, has always been very loyal to me but over the past few weeks he has become FIERCELY protective of me. If we are outside and someone walks down the street he pushes me towards the house whining and staring them down. If my husband is gone he is very vigilant and jumps at every noise. He guards the door like a soldier when we are alone and will not leave my side. My husband says that when I am gone he lays against the door or stares out the window and cries until I come home. I saw this as a good thing at first but recently it's gotten so that I can't leave the room without him. If i get out of his sight at all he lays down and cries and yelps until I return. He climbs into my lap every chance he gets and nuzzles my chest and smothers me with "kisses". He used to be affectionate with my husband as well but lately he's seemed to want nothing to do with him and is getting more protective of me. Our little guy, Yoda has recently started doing the same thing. He throws a fit if he can not see me from where he is and when I let him he is in my lap nuzzling and licking my chest. The other night the lab mix, Obi, had a sudden episode of aggression with my husband and bit him three times. We were both shocked. When I was between them Obi was fine but if my husband stepped between us he became aggressive again. He has been very defiant with my husband but obeys me like an angel. Both of the dogs were neutered before we adopted them. It doesn't seem to be territorial or anything. It's more like fear or protection. Any ideas what may be going on?
Yeah it sounds like Obi has gradually become a pack leader in your family and therefore he tries to set his own rules. He thinks he's in charge and so he needs to protect your from everyone and everything including your husband! In other words Obi decides what you are and aren't allowed to do, he decides when other people including your husband are and aren't allowed to approach you. Usually they aren't because Obi has decided so for whatever reason. That reason can be fear that something bad will happen to you, or it can be possessiveness. This is not the way a dog should behave, and being constantly in charge makes him stressed and nervous all the time. He just can't relax and be a normal self, a happy dog, because he thinks he has a lot of 'duties'. If left uncorrected this can result in more aggression and behavior problems in the future.
What you and your husband should do is to start building proper hierarchy in your household. Proper hierarchy means that any human in the family has a higher rank than the dogs, and the people decide what dogs should and shouldn't do, not vice versa. Here's a good article about what you can do to achieve that - http://mysmelly.com/content/dogs/how-to-become-the-alpha-dog.htm

As you progress your other dog's behavior should improve too. Just don't forget to treat Yoda the same way you treat Obi so the hierarchy is clear for everybody.
So basically you shouldn't allow him do whatever he wants. Just a few suggestions after reading your post 2nd time.

- Don't let him (and Yoda) climb on your lap unless you've invited him to do so.
- If you see him guarding the door command him to go to his crate (if he's crate trained, if not I recommend that you do that because it's a very good thing to deal and prevent separation anxiety).
- Command him to sit and wait a few seconds or minutes every time before you give him his meal. This will teach him that you are in charge of his bowls - a small step towards making him realize you are in charge of everything. This should also prevent food possessiveness and aggression.
- When he stars whining, crying or yelping for whatever reason don't try to comfort him with nice words, petting and cuddling as this will reinforce the bad behavior. Instead, ignore him until he's calm, and give him affection when he's calm and obedient. This way you'll reinforce the positive behavior.
- Get him used to being alone without you. Crate training is the way to go.

You'll find more tips in the article I gave you a link to in my previous post. Also you might want to read this one about crate training - http://mysmelly.com/content/dogs/crate-training-a-puppy-or-a-dog.htm
Oh and one more thing. He'll probably not let you claim the leading role easily so be persistent and confident. If it happens that his protests result in more aggression up to the point when you're afraid to communicate with him, it's best to seek a professional behaviorist's help! I don't think it will happen though because he's still a puppy and it's much easier to correct a pup's behavior than to deal with an adult dog.