@hungryowl Its unfortunate that she has decided a week before the intended event that she no longer wants to go, I appreciate its short notice and a shock, but I think if she has refunded the costs for both of you, she is acknowledging that, or have I got that wrong and she just refunded her money, leaving you with a paid break just for you and no-one to go with?
I think you are right to be upset but are looking at this from the wrong direction, you should be thinking why she is so adamant she now wants to cancel the weekend and is prepared to lose financially to do so?
Can I ask, you say your husband is a lot younger than you, is this the same husband you cheated on?
You sound young, vibrant and outgoing, not yet ready to slow down for a gentler existence without the boozy nights out, dancing and ying -yang with the opposite sex. Its great you are still there and are enjoying that type of life. Your younger husband will most likely still be on that phase too or at least he is young enough to see that as the norm.
Unfortunately for you, you friend is probably married to someone more her age and they are reaching that stage in their lives where they are slowing down, get their kicks from other things and no longer feel the need for the "crack" in life. This is perfectly normal and comes to us all at different stages in our life. She is just behind her husband but is getting there and it sounds like she has been telling you this and you are interpreting this as her being controlled by her husband and restricting your playmates joy de vivre. This is not boring, its just another phase in life and priorities change for many. Neither viewpoint is wrong, you just differ.
So you booked and paid for the break and she was to pay for the activities, but it seems that despite everything she has told you, you have decided that your needs trump hers and that you have gone off and planned everts that your friend has clearly told you she didn't want and she has told you it creates problems in her marriage.....and yet you persist., this is where it seems to have gone wrong. Its sounds to me like she has fired warning shots, which you chose to ignore.
Friendships change as you age and as many other posters have said, the only positive spin would be that you are at different life stages. She is struggling, you know that, would it really have hurt you to just had a girly weekend that was simply that, a girly weekend doing shopping, maybe a show and nice meal, quality talking time. You claim you have tried to support her, why is that too much, why does it have to be all about your wants and desires?
You have a choice to make, if she hasn't already made it for you.
You can accept the change in the friendship, to female companionship, mutual support and openness and a calmer activity range, or you can accept that the relationship has run its course.
Forgive me but you sound like you still enjoy the crack, the chase with men, whether you mean to follow though or not and she is past that. Its not desertion, or abandonment, its development. She has been honest about her wants and needs and you have tried to override them and continue as you want the relationship to be. And that is fine, if that is the lifestyle you want, but she is clearly signalling, that she does not, for whatever reason. You may feel her husband is controlling but you are trying to control her too and she is prioritising her marriage.
Sorry, I know I am not explaining this well but, its time for a change, either a change in your social relationship with her or walk away in a friendly fashion and for you to seek someone more alike in their needs to socialise with.
Big hugs OP, its tough when your much loved friends go in a different direction from you, but it doesn't have to be daggers at dawn,