<human>: Can you give me the gist of the text in a nutshell?

So my (31M) girlfriend (26F) recently returned from a 4 week backpacking trip through Thialand and Lao with some friends. I had planned on joining them but financial issue stopped that. So she wanted the trip to be a life changing spiritual trip, but it fell short of that. Turned into mostly a tourism spring break kinda trip.

So while travelling she met a group of guys from the UK who had all been traveling south east Asia. Some longer than others. 2 of them had saved up enough money to quit their jobs and live the dream of being a free soul. Another hadn't really saved any money and was just winging it. She became very close to these guys during the trip. Eventually she had to return home while they all kept travelling. 

So all of this happened back in February, and it's now June. She has been entertaining the idea of saving enough money to quit her job and move to Australia. Stay there long enough and save money to hop over to New Zealand. Then do the same there, and finish off in the UK where she meets up with some of these guys she met on her trip. 

All said and done the trip should only take 3-4 years... We've been together for 18 months, we live together and are pretty happy. While she was gone for those 4 weeks I was an emotional mess. Just so sad and depressed. I don't really know how to deal with this. She has basically given our relationship an unspecified expiration date. I do love her, but I don't know how well I can cope with the separation for 3-4 years. Really looking for advice on how I should be reacting to this.
<bot>: GF of 18 months caught the travel bug. Wants to move to Australia, then new Zealand, then the UK. With or without me. What should I do? How would a normal person react in this situation?