Without pointing fingers at anyone, I will just make the point that flexibility is a positive attribute when on Cozumel (when anywhere, actually, but especially when one is on vacation). If things don't pan out exactly as expected, then roll with it and find another way to glean a positive experience from whatever is going on.
Years ago, my wife and I got into a stupid argument on the plane on the way to Cozumel, and it negatively affected our whole trip. I'm not going to embarass myself by telling what the issue was that started it but suffice to say it was trivial in the extreme. It was really stupid on both our parts to let it get to the "fighting about fighting" stage.
Now, we have our official "no fights" toast on the plane, and we consciously table any "dangerous" discussions until after we get home. Additionally (from another incident on the same trip), my wife is not allowed to consume tequila and caffeine together (her rule, not mine) while on vacation.
Island time is too dearly won to spoil it with negativity, and sometimes that means rolling with a punch or two for the sake of the bigger picture. A mantra that I read somewhere and use a lot is "I am going to have to get over this someday. Why not now?"
Peace,