I think your BIL is being very unfair. You offered him a wonderful gift. If he couldn't go within the time you designated, he should have voiced his gratitude for the offer, but declined. It's pretty selfish to ask you to change your plans when you're the owners and you gave him several months to chose. What will the trip be like? Will he dictate when and where you will go and what you will eat? Maybe you could make him understand better, if you let him know the cash value of the size of your accommodations for the period he is asking and the period you are offering. Also, maybe if you gently explain to your husband that by changing, it will cost you so much more in points and that although you really are looking forward to taking his brother and your nephews, you really want to have some special time for just the two of you and if you go in March, you will have to lose that special time. We go twice a year for about ten days each time. One time is for family and one time is just for us. We pick the time and when we invite anyone, we tell them when we are going and if they can join us. Since 1993, noone has ever said that they couldn't make the time that we picked. The only unfortunate incident I have had is having a couple invite themselves along on one of the trips when we had already invited another couple. It happened once and believe me we learned a lesson and it has never happened again. Remember you have worked hard for this and it's for you and your husband. Share it when you chose to share it. Do not allow yourself to feel guilty. You are being wonderful by the fact that you have and are planning trips to include others. Don't let it ruin the future trips for you and your husband. Good Luck!