Oh hun I totally know how you're feeling. If you look at my posts you can see I've been a complete mess since my boyfriend of nearly 4 years broke up with me. He too did the same, told me he loved me all the time and was completely adoring of me, only to end it all in about 10 minutes outside my work.
Did he say how long his been feeling like this? I would advise against the holiday as there is no way you can go as friends on a couples holiday as you were once together. You will be there hoping for a reconciliation and if he doesn't feel the same you will spend the whole time feeling like crap - it will be no holiday!! If he is serious and there is no going back, you need to try really hard to cut contact. I know it's probably unthinkable at the moment, but trust me from experience - it really does make everything 100 times harder and you will not move on. I am still in touch with my ex and sometimes I feel fine with it but if I'm really honest I'm not moving on as I should and am just prolonging the process. You need to spend lots of time with your friends and look after yourself xx

-- Sorry just reread your post and saw that he said you should go alone, not that he is going too. Still this is not a good idea as you will be thinking about how it should have been with both of you there. If you do take a holiday do it with a group of single girl friends.

God it's like hearing myself! For the past 3 months I have been going over and over in my head - how can I go from being the most important thing in his life to no more than just another girl he knows in what seems like overnight??? I know we had problems, but it was always me that spoke about the problems and tried to fix them. Whenever I did have doubts I'd ask him and he'd reassure me that everything was fine, he had a fantastic time with me and that he didn't know what he'd do without me. People on here have told me that he must have been thinking it through for a longer than the week he told me he'd been thinking about it, but had obviously not let on. I know that this makes sense, but then I always thought that I could read him really well. I also think that my ex is very stubborn so it wouldn't have mattered if he'd thought it for a day - once he makes his decision that's it and there's nothing anyone can do about it. Maybe it just clicks in their brain all of a sudden! How much have you spoken to him since it happened? Have you seen him?

Maybe the holiday would do you good, have you got any single friends that can go too? BTW how old are you?

Sorry to hear about your break up, it really is such an awful feeling, many of us can sympathise with what you are going through. I remember my relationship ended with my ex, we had been together three years, it just seemed so strange, it takes a while to not seeing / speaking to someone you have been so close to for so long.
You DO get through it though hon, and better after all, that he has ended it than stayed with you when his heart wasn't in it. That's not fair to either of you.
Re. the holiday I would be tempted to say go - you have been looking forward to it for ages and a change of scenery could be good for you. Make sure you have plenty of distractions though, take some good books, book trips, do fun spontaneous things.
Take care of yourself hon, make sure you get pleny of fluid and eat well, you will get through this. x