I am looking for a good word to describe and emphasize a duration of time in a different environment, where the relationship between two people is "unaffected" by the worries of their usual environment.
A couple of words that came to mind were "unaffected" and "untainted," but they don't feel quite right with what I'm trying to describe. I feel like those words imply too much negativity.
Do you have any suggestions?
The first appropriate adjective that comes to mind is carefree. It very much implies an environment in which the usual cares and worries of life are significantly reduced in importance.
If you want a noun, the entire period of time might be referred to as a getaway. This word has various meanings, but the connotations here clearly refer to the fact that the two people are escaping their usual troubles and daily routines, hence "getting away".
Slightly less apt adjectives to describe such a time (almost synonyms to carefree) might be untroubled, blithe, or laid-back. These adjectives could be applied to either the time the persons spent together or the persons themselves, really. Other words like buoyant or light-hearted however, apply better to the moods of the persons themselves.
Finally, if you are looking for verbs of the form "They were [verb] by worries.", you could use:
These are all examples of attributive verbs.
If you're looking for an un-word, here are some thought-starters in italics :
Finally, Jack and Jill reached happyland. They spent a few blissful days at the top of the hill, secluded from the rest of the world. The brief interregnum at the hilltop resort rekindled their love for each other. Far removed from real-life, their relationship was unconstrained / untroubled / unfettered / uninhibited / unhindered / unimpeded/ unhampered by the circumstances that caused them to sell the house to pay for their exotic holiday in the first place.
If you're not looking for an un-word, you could say :
Jack and Jill were insulated / isolated / removed / cocooned from their worries.
If you're looking for an "in-between-stress-filled-times" kind of word, you could use:
break, sabbatical, holiday, jaunt, hiatus, idyll, respite, interlude, interregnum, interval
Neutral is often used to refer to such an environment.
A retreat is a period of time away from usual worries. From previous answer with many words, break, sabbatical, hiatus, respite, and interlude seem to me more a propos than do holiday, jaunt, idyll, interregnum, and interval. For example, I think the latter two words connote "a time between" more so than "a time away from cares". I associate jaunt with traveling rather than respite, and associate holiday and idyll with activities for pleasure rather than with just being away from the usual cares.
