So to preface my dilemma, I have to note that my dad was poor growing up and has since built his wealth to become a multi-millionaire. Because he wasn't afforded any luxuries as a child, he has the mentality that he wants to treat his children to things he never had, including a grand wedding. I'm the only daughter so my parents are going all out on our wedding. Our guest list is up to 360 people. My parents are very traditional in thinking that they should foot the bill for the entire thing. That being said, my future MIL pulled me aside before the wedding planning began and insisted on paying for the flowers. She said she and her husband would provide a budget and I would have to stick to it, without any monetary input of my own, or from my parents. I tried to protest, but she was so adamant, I conceded. The budget she gave wasn't even half of what our wedding planner told us it would cost to put even basic flowers on every table. I was heartbroken and torn. The flowers to me, make or break the room, and with a black tie wedding at my dream venue, I didn't want to settle for anything less than my dream, especially knowing my parents could easily provide the flowers I want without financial burden. When my future MIL finally saw the venue, and found out the guest count, she doubled the budget, which still couldn't pay for everything I envisioned, but was more generous than I ever expected from her. She recently told my fiance that they're limited on the rehearsal dinner because they're paying 3x as much on flowers as they paid for his older brother's wedding. I know they're not as well off as my parents, and I feel bad knowing that they're probably stressed paying for my flowers, when my parents wouldn't think twice about footing the bill. My future MIL has already found the florist and put down a deposit though, and now my dad is trying to find a way to secretly pay for most of the bill behind her back so they don't get strapped with such a large burden. How do we politely decline my future in-law's offer, without offending them?