I've had similar experience with family gatherings, after BD we visited both my parents and in-laws a few times. esp with my parents since we usually stay over night there when visiting. I used to get nervous about not knowing whether he would still be staying with us...how things will play out...what do I say..etc.
In my opinion, if you're not ready to share the situation with others, it takes some practice and you will need standard answers to common Qs. With time you will get better at it. For example, my parents were asking me all these details about his work/job etc like they usually do and I couldn't answer most of them because H and I haven't been talking that much. I learn to give generic answers and change the subject. or I just say I honestly don't know. That's my answer to most Qs my kids ask me as well, "Why does daddy have another business dinner?" - "I don't know, you'll have to ask him." Basically I stopped answering for him or on his behalf.
For Example:
How is H?: "He's been really busy." or "He's been under a lot of stress." Anything related to H: "I don't know, why don't you ask him?", "I don't know, I'm not sure what he's thinking." Scheduling: "I don't know, I don't know his full schedule." or "I don't know, I will have to check our schedule."
You can say to him, "I'm going to visit your mom, if you are not coming along I will tell her that you are doing ______".
It works with me and my H when I know he's not gonna show up and I know he'll stick to a provided script.
