You have had one date with this person, and your partner wants to buy this new person an engagement ring already?
What's going to be brought on the second date - a moving van?
Am I missing something, but this seems rather... fast. One of the tenets of making poly work that I heard was to take things at the speed that everyone is comfortable. Sounds like this isn't being done here at all. (Presumably from the fact that you have mentioned it you aren't keen on either the ring or the vacation.)
Maybe having a sit-down with the three of you and having a talk about expectations, hopes and dreams might be a good idea - and don't be afraid to speak up and say "look, I really want to see where this can go, but this is too fast"
Please check out The Birdcage - an open, friendly Polyamory forum for all parts of New York State
"Listen, or your tongue will make you deaf." - Native American Proverb