I have a suggestion....is it possible you meet for say...two nights, now before the 14 week trip?
Don't know about open non romantic relationships, but my first poly relationship was with a friend I met online, and we flirted and talked for a few years (and met once) before we were intimate, and we had a lot of chemical attraction and lust built up over those few years. We had a great 5 days when we did finally have sex, and then the next time we met I had absolutely zero desire to even kiss him. That's why I think a brief meeting before something as extreme as a two week trip would make a lot of sense. I can't even picture spending more than 5 days with a great friend unless I'd spent lots of time with them in person, it seems like a recipe for disaster. Fuck, my ex husband/best friend and I went to Europe several years ago and I still ran out tolerance after being with him 24 hours a day after 8 days, much more stressful than living with each other for 12 years. What I'm trying to say is...two WEEKS?
And I'm sure you're aware of this, but "don't fall in love" is about as far away from polyamory as you can get, so if you don't get the advice that fits your situation here, (cause it'll probably be mentioned that you can't control if you fall in love or not - and you seem to want to stress ...love? no not love, never love!!!) you might want to look in more of a swinging forum (I'd say open relationship forums, but I actually realize I don't know of any)
And for dealing with your feelings of jealousy and all? Opening Up
. Great book.