That's a tough one. I'm so your going through this and she is taking over on planning your AHR. Maybe if there is another way to explain or ask if you can do more things your way. Possibly change things that are being done at the AHR? Are you doing a full sit-down dinner or is it more casual? If you can let her have some of her ways with things but keep the party light and casual enough it should be more fun mingling than formal affair where you and your FI are on display for everyone's viewing pleasure. I hope you can find a way to get her to understand what your vision is, keep reminding her that this is still about you and your hubby.