We've just celebrated our 2nd year anniversary and I want to break up. What should I do?

Your worried way to much about how everyone else will feel. If your not happy in your relationship then end it as soon as possible. It's your life and you shouldn't live another day unhappy. Since you already payed for the trip, go on it but if your so serious about this break up, break up with him, move out, and reunite in two months just for that day. You have to live your life for yourself and not for everyone else around you. It's going to be hard, of course but sometimes in order for you to be happy you have to make someone else unhappy. Live your life for you.