There are several possibilities. One is that they are not fully over you yet and seeing your stories gives them a sense of closeness. Another is that they are trying to make sure you're not doing better without them, which is a bit of an ego - driven thing. It's also possible that they accidentally clicked on your story and now keep watching out of habit.
One dumper coming back story could be that the dumper realized they made a huge mistake after leaving. They might have thought they could find someone better but then found out that the person they dumped was truly special. For example, a guy dumped his girlfriend because he was attracted to someone else at work. But after a while, he saw that the new person was just interested in his money and status. Then he remembered all the genuine love and care from his ex - girlfriend and came back to her, begging for forgiveness.
It could be your followers on social media who are interested in your content and keep an eye on your stories. Sometimes, it might also be random people who stumble upon them and find them engaging.
Not necessarily. It could be just a casual thing. She might watch stories from many people. But if she always watches yours quickly or interacts with you about them, it could be more significant.
Not necessarily. If it makes you uncomfortable, you can always limit their access. But it might just be a harmless thing on their part, like casual curiosity.
It could mean a lot of things. Maybe they're still curious about your life. Or perhaps they miss you on some level and this is their way of staying connected without actually reaching out.
It could mean that your crush is interested in you. Watching your stories might be their way of keeping up with what's going on in your life without directly interacting.