Lise, the main character of the story "The Ring", is a young woman who seems both idealistic and prone to live in a fantasy world. This is not entirely her fault: She is a privileged child who has grown up in a closely-guarded situation. So guarded indeed that Lisa seems to rebel in her want to marry her husband, who is older and less rich than she is.
Once her marriage finally happens, she lives in a bliss so extreme that she feels as if she were playing, and not living life. This is a dangerous state of mind, as it may bring anyone to think of life as a big playhouse, not knowing how little control of it we really have.
We can assume from all this that Lise is impulsive, exaggerated, and overpowering in her thoughts and actions. This being said, we can conclude that the encounter that she has in the glade with the thief opens up yet another door that Lise has not explored: The wild and evil (and often exciting) side of life.
Judging by her previous actions, she is more than likely going to make a huge deal out of the situation in the glade. However, lest we forget the possibility that the encounter in the glade is a metaphor for an actual sexual indiscretion,which would not be a surprise either. Either way, the first thing she does impulsively and instinctively is to give up her wedding ring to the thief- which he ultimately rejects. Therefore, when Lise thinks that it is "all over" we can conclude that it is for her: Her fantasy about marriage, love, and desire is completely faded now. She has sort of tasted something she has never experienced before in the form of a rugged, rogue thief. Maybe her sexuality has suddenly awoken. Maybe it is just her natural curiosity hitting again.
Conclusively, what is over for Lisa is the fake illusion of her joy and eternal love for her husband. That, in turn, could be the end of her life as she knows it.