How is monogamy NOT a sign of true love???? Not forced monogamy, but the person only wanting to be with you by choice and natural inclination???! What is left sacred if you share your body and your emotions/love with someone else????
I used to see things this way that you're speaking to, but over the years something completely flipped inside me, and now this perspective is alien and strange to me. You see, I
know in my bones that exclusivity is in no way a sign of truer love than non-exclusivity; and I know how much healing, joy, and happiness has come to my 13 year partnership with my Kevin when he or I opened up to loving others (though those relatioships didn't last).
"What is left sacred if you share your body and your emotions/love with someone else?"
My goodness! It's all sacred! Every relationship we have is unique, special, entirely itself, and irreplacable. Each of them are an opportunity to open into greater love, joy, freedom, etc.... Each can -- and really should -- enhance all of our other relationships, by enhancing our own lives, bringing sparkles of brightness to our hearts.
Love grows by giving it away, by dispersing it -- not by hoarding or by fearfully protecting and sheilding ourselves from involvement.
I see that you are sexually frustrated because your libido and that of your partner are a mismatch--and that you can't expand your sexual experience as "just sex" because your sex is so much connected with feeling/emotion/love. (Good for you that you're whole in this latter way!) -- There is no shame or guilt necessary for you to want to be sexually fulfilled, my friend! There's nothing "wrong" ... "dirty" ... about your body or about your desire to commune with another/others bodily. Non-monogamy isn't filthy! Loving multiply can be intensely wholesome, and can even enhance your joy, love and intimacy with your present partner. You CAN have your cake and eat it too.
I've said it before in this forum, and it's time to say it again:
Your best gift to those you love is your own happiness. Now... meditate upon that carefully and long. Write it down and stick it on your wall, and meditate upon that daily until you have the A-ha! moment, because what I just said is true, and profound. When you are happy you give your best to those you love. It's a fact. Learn it well.