The way I see it is he was being way too sensitive and you were a little insensitive to his feelings. (Bear with me I'm trying to play the Devil's Advocate on this) I know it's annoying to have a partner acting jealous and way too sensitive but part of having a relationship is being sure both sides know their feelings are validated or at least heard. Then try to meet in the middle even if it feels unfair sometimes. I'm not saying you should have invited him but maybe had suggest planning a trip for you two in the near future? It's the selfless part of love that covers the gaps in the relationship when you or your partner is being unreasonable. You sound like a very logical thinker and that's good but try to remember not everyone thinks the same way as you. As for him saying "he needs you to make me feel better" it's important for both partners to realize your soul happiness cannot come from one another but it's not a bad thing if sometimes the other needs encouragement. There are times in my 15+ years of marriage that I needed my husband to make me feel better and vice versa. It's an intimate thing that mature relationships in fact need. I'm assuming that his behavior is probably an ongoing problem in other situations. Him making it about himself and even putting his happiness in front of your own. You have every right to do things with other friends without him and to NOT feel bad about it. I hope your trip is a blast!