If your in-laws don't want to come to your house for dinner, it's essential to be understanding and respectful of their decision. Here are some things you can say:
"That's completely okay; we understand. If you change your mind in the future, you're always welcome."
"No problem at all. We can plan to get together another time when it works better for everyone."
"If you prefer not to come over, maybe we could meet up at a restaurant or another location that you'd feel more comfortable with."
"We'll miss having you over, but we respect your decision. Let's find another way to spend some quality time together."
"If there's any specific reason you're hesitant to come over, please feel free to share. We want you to feel at ease when you visit."
"We could also do a virtual dinner if you'd like to stay connected even if you can't make it in person."
"We value your company, but we understand if you have other plans or commitments. Just let us know when you're available, and we can plan something accordingly."
Remember, everyone has their reasons for declining an invitation, and it's essential to be gracious and understanding. Don't take it personally, and keep the lines of communication open for future gatherings.