Rekindling Old Flames

Imagine a setting where years have passed and you've arranged a meet-up as 'exes', rekindling the flame that was once extinguished. The boyfriend's role is to convince his ex (his present girlfriend) how much he has changed over the years and how he realizes she was the one, trying to win her back with his newfound maturity and charm.
The ex-girlfriend (the boyfriend's current partner) is initially resistant, bringing up their past issues, but she does feel the pull towards her ex, finding it hard to ignore the matured, changed version before her eyes.
As the conversation deepens, with heart-touching confessions, passionate arguments, and cute jests from the past re-emerging, the old flame flickers back to life, culminating in a passionate reconnection that surpasses the memory of their past relationship.

To set the mood, you may arrange your living room to give off a casual meet-up vibe. You can have some old pictures from your past dated years, love letters, or any remarkable mementos you've held onto. They can trigger old memories and emotions, making the roleplay more realistic and compelling.
You both should decide upon your backstory as exes. It's an important part of the preparation as it allows the story to flow naturally. Dig into your past, remember your first date, why you fell for each other. Recreating that can create an environment full of tension and romantic nostalgia.
Last but not least, you could both sit down and list all the silly arguments, beautiful moments and heartbreaking incidents from their imaginary past to make the scenario as real and rich as possible.

Maintain the authenticity of the characters. You're exes trying to figure out if getting back together is plausible, so your actions and choices should reflect that.
Props like old photographs and letters written by the 'boyfriend' to his 'ex-girlfriend' can add a level of depth and realism to this scenario, making it that much more exciting and engrossing.
Finally, always remember to respect your partner's boundaries. While this roleplay scenario can get understandably heavy and intense, it's essential to keep things enjoyable and comfortable for both parties involved.