When you open up later in life or in the relationship it will most probably be difficult. When it's always been in both your nature and long standing (and I don't mean quantity of people but time within that mindset) it's also easier to navigate situations. Personally we both avoid getting into sexual situations with people we don't both find attractive. This means quite little action overall. We have the freedom to explore individually, which is easier than getting us both to equal levels of attraction towards someone else or another couple. But that said...very few compatible women accept getting involved with a married man with kids...while in my case most men assume I'm lying, don't care anyway and are just interested in their own satisfaction. Hence... despite the freedom...very little action individually as well.
I'd second all the advice given about communicating. It's crucial. If you are a good team...even if one gets hurt...or regrets...or gets a little sti surprise... because uhm...it's a reality to consider...you'll both work through it and come out stronger.
Alternatively if shit gets too complicated...just pause or quit the lifestyle. Random sex isn't worth a good romantic relationship. My opinion out of lived experience here!
Take care...and happy playing! 😁