And that’s just between the two of you. When you get a new roommate or you adopt a cat from the shelter, he sees immediately that things have changed. He starts to get a little sick with worry as the plot thickens between the players. He has to figure out how to build new relationships, and it will take time to build trust and rapport. Bonds are not formed overnight. In the meantime he might be a little concerned about how these additions are going to add up for him as the numbers rise. Social complexity grows with each of these new members, and all the little things about personalities and relationships can stack up pretty quickly.

Your girlfriend has far less patience for his whining than you do, and doesn’t want a dog in the bed. This means the noisy evening games of fetch and nightly snuggling are a thing of the past. The cat gets way better-smelling food than he does, and you won’t let him have any. Patterns he could hang his hat on—moments you shared and routines you both adored—have been broken.

It’s understandable that your dog could be disturbed by all the challenges and changes in your life. But you might be surprised, and even a little unnerved, to learn just how dependent your dog is on you to be the captain of this ship. And even he knows that without a captain, this ship is going nowhere. He is looking to you for a sense of confidence that you have some idea about what the heck is going on. He’s looking to you for the rules, the structure, and the plan.

He has no way of knowing how to negotiate carpools of strange people diving into your backseat, crowds of inappropriately friendly “dog people,” well-meaning neighbors who let themselves into the backyard to return a weed trimmer, and an incredible buffet spread on your dining room table that he is expected to completely ignore. His best ideas of how to handle these situations could include a well-placed bite to what looks like an intruder or a grateful gorging on turkey and dressing.

Our job is to create a sense of a tight ship, one that our dog will trust to be afloat at all times. He needs to feel safe or he will be in a constant state of anxiety. While it’s not a perfect metaphor, think about how you would feel if you were on a boat in the middle of the ocean with no way to get off, no idea of where you were headed, and no sense of stability or predictability day to day. Most likely, you’d want a captain with a plan.