Curious if one structure is better than the other for serious tantra practitioners.

I personally feel it would be hard for me to reach a level of surrender and devotional love if my partner or I are having casual sex elsewhere. Furthermore, I have no interest in casual sex or having multiple partners. Tantric sex is so fulfilling with one person that it feels we become the Universe, totally satisfied and totally fulfilled. I don't see why I would crave sex with anyone else in that state of complete universal fulfillment.

My friend, who is a preacher of non monogamous lifestyle, told me about the book The Ethical Slut. It mentions that a poly/open relationship lifestyle can "open spiritual awareness". Furthermore, the author argues that poly/open lifestyle can be a "spiritual path".

My friend argues that non monogamous relationships are more "awake", or "natural" or "good" path and monogamy is culturally and socially conditioned trap. She argued that if I want to progress spiritually, non monogamy may be a better choice. My gut disagrees.

From my personal experience, I find it hard to imagine building a strong spiritual connection if the energy is dissipated to 15 other casual sex partners.

I'm curious to hear your thoughts on this subject