Thank you all so much for reading this post and for offering your advice!
I'm elated to announce to you that I think we've found a wonderful solution our problem.
My boyfriend and I were talking again today and after a little stay in a fog of misunderstanding, I realized something: That taking this whole "sleeping with other people" idea on a case-by-case basis feels worlds better to both of us than trying to convince ourselfs to approve of any sexual situation that may arise.
I realized that there
is a situation in which I would be turned on by seeing my boyfriend with another woman. The key is that I would have to be attracted to the other woman!
I've had crushes on girls before. In these crushes I've had sexual fantasies and even enjoyed kissing or being intimate with the girls to whom I was attracted. If the situation is that I find a girl to whom I'm attracted and then get to be involved in the whole process of my boyfriend enjoying her, that I could enjoy their sexual interaction just as much as he does. I'm turned on by both parties and I can enjoy living vicariously through them (and hopefully participating as well!

)
The fact that my partner has deemed it ok for me to say "no" is so liberating. If I am uncomfortable with a situation, it is not the end of our relationship, it just wasn't the right time or the right person. The fact is that there
are "right people" out there and if we run into them and have the opportunity, that we could both enjoy the experience of either of us playing with them, together or separate.
We're just going to take it day by day, situation by situation, enjoying what is instead of hoping for or dreading what could be. We both believe that you draw to you what you put into the world. We've decided to put happiness and a carefree life perspective into our realm and I'm sure that that's what we'll get back. If that includes our special lady or special man or special couple (haha), wonderful! If not, we will simply continue to enjoy each other in a loving, listening, alive relationship, ready for whatever comes our way.
Thank you all for your input! I hope those of you who live happily and freely continue to receive all of those wonderful blessings and I hope that those of you who want for anything are able to find clarity and joy very soon!
<3