There is a big difference in fantasy and reality. For both of you. Too many people let the fantasy play out without giving the reality enough thought. If she’s still dropping these hints she’s looking for you to give approval or as a minimum she’s wants to include you in her fantasy. If your relationship is strong enough and you’re both emotionally mature enough to invite a male into the mix…then you could have a lot of fun. If it’s not….you’re headed for trouble. When she brings it up again ask if she really wants to try one. Find out what she’s looking for. To include you? For you to watch ? If you decide to proceed …set some rules and boundaries. You can always modify your rules to suit your needs and desires as you gain some experience. Just a word of caution. We’ve known many people who have turned fantasy into reality and end ended up splitting if you both don’t get when you want. We also know a lot of people who have got amazing pleasure.
Talk it to through. Several times. Talk about the potential risks. If you’re both still willing to try ….it will happen as you’ll both subconsciously be looking for the new opportunities when you’re at a bar and meet singles.
Best of luck!