<human>: Can you give me the gist of the text in a nutshell?

My girlfriend and I have been dating for a year, and since high school. We are each other's firsts, but we've dated before each other, just not sex. Anyways, she mentioned the other day how she thinks we should, at some point in time, try sleeping with other people before we got married so that 1) we didn't sleep with only one person our whole lives and 2) we are sure what we have is special compared to sleeping with someone else. She said she doesn't want to resent me in the future for something that she can't control right now because someone she knows is still dating her high school boyfriend who was her first and only and now hates her boyfriend. So my girlfriend doesn't want this to happen to us. She doesn't want this anytime soon, I even asked if she wanted to next summer and she said that was probably too soon IF we ever did it. We are both very sexual people, we have sex at least once a day, most of the time more than that. She is amazing and caring and we have an awesome relationship. I have always wanted a threeway like most other guys, but she does not want that. She wants a completely separate night with different people, like a couple swap. I've done research and it says not to couple swap to fix a relationship, but ours isn't in need of fixing, everything is totally fine. This happens to be a sexual fantasy of mine, but the kind that I don't know if I would actually ever go through with. So what should I do? Tell her no and risk her being unhappy and possibly leaving in the future? Or go through with it and deal with the possible consequences? Or something else?
<bot>: My girlfriend wants to us to sleep with other people before we get married or settle down. I might be fine with it, but I don't know. What should I do?