I had the same issue as I wanted to be considerate of everyone's financial situation. My FI was dead set again Mexico also. It wasn't worth the fight so we both chose Jamaica and most of my guest are staying 3 or 4 nights. They have some beautiful resorts. I would suggest that wherever you choose, don't require your guests to stay a certain length of time. I figured if people are willing to take the time and spend money, then they should be able to determine their length of stay. Good luck and congrats!