One way is to show a lack of enthusiasm. Don't give them much of a reaction when they start the story. Just say 'Hmm' in a rather flat tone. They might get the hint that you're not into it and stop. Also, you can excuse yourself briefly. Say 'I need to quickly check on something' and when you come back, start a new topic.
Tell them how you feel in a kind way. Say 'I'm feeling a bit tired today and I think I can't really focus on that kind of story right now. Can we talk about something that can cheer me up?' This shows that it's not their story that's the problem, but your current state, while still getting your point across that you don't want to hear it.
Just be straightforward and tell them that you're not interested in hearing those stories. For example, you can say 'I'm not in the mood for these kinds of stories, let's talk about something else.'
Well, you might try something like, 'I'm having a hard time staying engaged with this story. Maybe we could talk about something that's a bit more exciting for both of us?' That way, you're being kind but still getting your point across.
You can say something like 'I really enjoyed that story the first time, but let's talk about something new now.'
Another way is to start a new topic that is more concise. For example, 'That's a great story, but I just remembered something really important I wanted to share with you. It'll only take a minute.' By doing this, you shift the focus away from the long - drawn - out story.
You could try saying something like, 'I'm really interested, but could we come back to this a bit later?' That's a gentle way to interrupt.
You can also try to shift the focus. For instance, 'Your story is great, but I really wanted to share something with you quickly.' Then start talking about a different topic briefly, so he gets distracted from his endless story.
You can directly tell them that such stories are inappropriate and make you uncomfortable. Be firm in your stance.
You can also joke about it. Say something like 'Dad, that story is like a broken record! Let's hear something different for a change.' Using humor can soften the message and make it more likely that they won't be offended when you ask them to stop repeating the same story.
You can simply tell them that it's inappropriate. Just be straightforward and say that such stories are not welcome.
If it's a friend, you can directly and firmly tell them that it's not acceptable behavior. Explain that it violates privacy and is disrespectful. For example, say 'That's really inappropriate. You should respect your partner's privacy.'