It could be that they don't have the time or maybe they don't want to think about the past and seeing your stories reminds them. Another possibility is that they have new things going on in their life and have less focus on social media in general.
Well, maybe I just got too busy lately. There are so many things going on in my life right now, like work and other personal stuff, that I don't have as much time to check out stories as before.
Maybe he lost interest. People's interests can change over time. He might have found other things more engaging or he could be busy with his own life and doesn't have time to keep up with your stories anymore.
Perhaps she had some personal issues or distractions that prevented her from giving your stories the attention they deserve. It might not have anything to do with you or your stories specifically.
Perhaps he's having some personal issues or going through a phase where he's not in the mood for any stories at all. It might not have anything to do with yours specifically.