My ex used to do similar things ALL THE TIME...he's just very sociable and impulsive. We did finally get to an understanding that he couldn't just invite 4 people over for hamburgers on sunday and not tell me until Sat afternoon when I had NO time to even shop for the food...this was back when I lived in Germany years ago, it was a 45 min trip to the commissary in a different town that was only open 5 days a week and I only shopped for enough food for the two of us at a time. so I would tell him...we have no hamburger meat, we have no buns, we have no toppings..what am I supposed to feed your friends?
now he did this one christmas when his mom first came to live with us, he invited all of his brothers and families to our house without telling me...I was already an anxious depressed mess at that point, I told him there was NO way I was cooking for 14 people. we went to golden corral instead, everyone ate all they could hold and everyone was happy.

We did however, host single soldiers for dinners over the holidays when we were overseas, I never minded that but it was also something we decided on together and he picked the guests.

I agree...maybe a sit down and have a discussion about making the decision to host guests a JOINT decision?