The issue isn't that Mono wants to add people to his life, it's how your relationship is changing. These outside people only see it through their glass window as they look in. They don't see (or don't care) how the interpersonal dynamic between the two of you is shifting and causing fears and insecurities to rise to the surface. This is new and unexplored territory for the two of you and there are so many twists and turns that with just a few missteps, things can go catastrophically wrong. Of course you are going to be terrified and unsettled.
How many people freak out and see all the things that can go wrong, when their military spouse is deployed for the first time (or the first time in their relationship)? This is really no different.