Ok...I've heard your side and read all the posts in between and now I am going to give my 2 cents for what its worth. And I know I am going to get FLAMED for it but here it is....
First off, whether your daughter is 15, 16, or 17 is not the issue. She is not an adult of 18, 20 or 21. Like many before me have said in so many other words to avoid typing the words MORALS and VALUES because that is what we are really talking about. Why are you even taking this into consideration? Evidently as a parent you already know deep down that it shouldn't even be up for discussion. And what do you mean you know she will be mad. Who cares?? I think that is another problem. Kids are allowed to have too much say and input. No its NOT OK to take him on a family vacation and no its not ok for her to go with his family on vacations either. In fact, in my opinion, OVERNIGHT stays together ANYWHERE are out of the question until they become adults. I dont care what the "so-called" sleeping arrangements are or supposed to be. It's just too suggestive and accepted.
Next, you talk about how he aggravates your husband. Well thats enough reason right there. Just because your daughter thinks her BF is the sun and moon and stars doesnt mean everyone thinks that of him. You are willing to sacrifice your husbands happiness on vacation rather than disappoint your daughter???? WHAT!!!???? Since they are NOT married, you and the rest of your family indeed have a right NOT TO TOLERATE him unless you want to. And a family vacation is NOT the time to do that. You have other children to entertain. You dont want to be stressed or uncomfortable because those vibes will ruin everyone from having a good time.
I just find it hilarious when parents allow their childrens "FEELINGS" to dictate their parenting. I have an adult son (unmarried...but has a girlfriend), a 17 year old son(high school) and a 3 year old daughter. We take a family vacation every year. And for the past 3 years my DS(adult) has inquired about possibly taking his girlfriend. NOPE!!! Not happening!!! Until she is his WIFE, we do not include her. Now people can call me what they want. Once they become adults, they will do what they want and you cant control that. But you can control what they do in front of you and within your household. So to me, a family vacation is part of my household as it should be. There is no way my 17 year old would even come to me and SUGGEST if his girlfriend could come along. He may think about it, wish for it, but he sure wouldnt say it!! Because he has never been granted ANY authority over my values, morals and rules of my family and household.
Tell your daughter NO!!! And get on with your vacation plans. And do not give her the option to stay home with her father either. She is to do as you say until she becomes an adult. Are you kidding me?? I know, I know I may have gone above and beyond and may sound harsh. But the fact that someone would even STRUGGLE with the idea of disappointing their child for something they shouldnt even be considering when all the warning signs are there to JUST SAY NO!!!!