I found this part of his book most useful in thinking about the physical aspects of a relationship - not just an r/s with a pwBPD, but in general. Schnarch has identified three, of what he calls, “sexual mindsets”.

“There are different depths and ways of focusing on your partner. Each reflects how you relate in general. The tone of your connections may vary from event to event, but the overall character tends to be stable; it is determined more by your personal development than by how you feel about your partner at any given moment.”

He divides them into three categories: Sexual Trance, Partner Engagement, and Role Play. He says that “each has its own preferred physical technique, emotional tone, and style of engagement.”

• Sexual Trance is about a preference for focusing on bodily sensations and your own sensuality. For those whose preferred mind set or mode is Sexual Trance, the emphasis is on touching, on taking turns “giving or receiving”, on enjoying an almost altered state of consciousness which is comparable, Schnarch says, to “a drug high”.  This mindset, as he calls it, generally involves a fading away of the real world - a diminished sense of everyday reality. People for whom this mindset, or mode, is the preferred one generally do not like to talk during sex and tend to have their eyes closed more so than open.  
  
  “Trance state sex can be intimate if both people enjoy it and are good at it. But it can just as easily leave you feeling “used” and ignored—like your partner is using you as a fleshy sex toy—and he just tunes you out and focuses on his (or your) body”

• Role Play is the preference to experiment with different characters -  to inhabit different roles much the way a method actor might do. Costume, technique, voice, facial expression are important. Schnarch says “Just as your ability to maintain a clear sense of yourself allows you to get closer without fear of losing yourself, it also gives you the flexibility to take on a variety of roles without running into the awkward feeling, “That’s not me! And I won’t do it!” The clearer you are about “who you are,” the easier it is for you to take on, temporarily, a different persona—you can “blur your identity” without feeling phony. “
  
  Again, this can be intimate if both parties enjoy it and are happy to “go with the flow”. If one or the other does not, it can feel false, disturbing, even humiliating. If one does not want to play a part that goes outside one’s comfort zone, it can feel that whoever we actually are is not appreciated.

• Partner Engagement emphasizes your emotional bond with your partner. Physically, this involves foreplay with lots of eye contact, kissing, and hugging, face-to-face positions, sharing and mutual touch.
  
  If this is your preferred style, sex is about union and connection, and happens during one night stands as much as in tender and caring relationships. If you have a curiosity about a potential partner, you may be interested in how they will express themselves sexually. Within an established relationship, a sought afer ideal is to share something deep and special about each other, perhaps to merge in some sense and experience a mutual and heightened sense of aliveness.

According to Schnarch, there are different depths and ways of focusing on your partner. Each reflects how you relate in general. He says: "The tone of your interactions may vary from event to event, but the overall character of your interactions tends to be stable; it is determined much more by your level of personal development than by how you feel about your partner at any given moment, because you feel about your partner will in large part be determined by your level of personal development."

We conducted a member survey on the various innate sexual styles:


Click graph to enlarge
https://bpdfamily.com/message_board/index.php?topic=299932

By understanding the many faces of partner engagement we can more fully comprehend human sexuality and develop more respect for when it is beautiful and uplifting.

• Sexual predators who focus on their partner’s reactions but for purely sadistic reasons. Their own arousal and satisfaction depends upon specific desired responses elicited by particular means. The other is not seen as a separate human being whose individual reactions are of themselves interesting or arousing – only specific reactions are met with interest by the so-called predator. Generally this involves the pain or fear of another and a sense of control by the predator

• Opportunists are primarily focussed on their own sexual needs and having those filled by another. Sometimes it is likened to just preferring another body to masturbating. It can be fun and satisfying to both parties to have their physical needs filled without much emotional investment in the relationship or the outcome of a sexual meeting. This is not a problem, as long as both parties are on the same page about what is happening.

• Narcissistic Engagers use their partners to provide “ego strokes”, a way to get a reflected view of themselves as having sexual ability and being attractive. Our partners are, in this case, less important than how our sexual ability with that partner makes us feel about ourselves. If we manage to arouse our partners and satisfy them, we feel powerful and good about ourselves. If we don’t, we might feel angry ( or disappointed, or like failures, if we look a little deeper) and / or seek out another partner who does help us feel the way we want to about ourselves.  

• Other-validated people place a greater importance on others in their own right – we want to give pleasure and the ability to give it and see it’s effect on our partners makes us feel good. Making someone else happy in bed, makes us happy.  If we don’t see our efforts bringing about results, we may feel sad or like failures or somehow not good enough.  This might be the sexual equivalent of what we call co-dependency. In this mindset, we may find ourselves open to experimental sexual behaviour that our partner wants – but we do not feel entirely comfortable with, as one example.  We may find ourselves doing things that do not, in themselves, feel good or “right” to us, but our partner’s evident pleasure in this supercedes our own needs. Our partners matter more than we do in this case.

• Truly Connected - Here we see our partners as “a bona fide separate person” whose satisfaction is as important as one’s own. If we are truly connected, we are able to manage our sexual (and other) anxieties and insecurities, we are able to soothe ourselves. We are able to be intimate both emotionally and physically – to share ourselves openly, to accept the “core personality and potentials” of our partners and ourselves.   Our sense of self – sexually and otherwise – is our own and sexual expression (however experimental or playful) is just one aspect of how we are with our partner.
  
  There is trust which enhances our openness to our own sexuality and our sexual relationship. We are excited by the other person physically, emotionally, and intellectually. They matter to us and we are sure that we matter to them in the same way. Significantly, we matter to ourselves as much as they matter to us.

• Spiritual Union - The highest form of Partner Engagement, according to Schnarch, in which  we recognize completely that we are separate from our partner and yet can connect deeply and meaningfully. In this connection, we have a sense of something new being born – “Sex becomes a form of spiritual communion celebrating the mysteries of life."

Now the part on Sexual Mindsets I find extremely relatable and helpful!
I'm quite grateful to read about this, thank you!  

[Speaking as a person who has a history of abuse, learning and understanding my sexuality has been a complicated journey.  It has been pretty complicated due to my tendency to dissociate and in the past ~8 years I finally realized what was happening and mostly self taught my way into learning to remain present with my partner and manage triggers.]

I have never been one much for Role Play generally.  I get stage fright in some ways, and attempting such can cause anxiety.

So Sexual Trance is what I had known most of my life and enjoyed.

However, in the past ~10 yrs, I had found a partner that was very much more Partner Engagement like.  He insisted on a lot of eye contact and I came to really enjoy bringing this type of connection into sex as well.  

My partner after him, (most recent ex) we did combo Sexual Trance and Partner Engagement and I can certainly say that I felt most real and present with Partner Engagement type interactions over Sexual Trance ones.  

Sometimes Partner Engagement type interactions felt scary as there felt like there was more risk involved.  It felt like a mistake could more easily be made to turn other partner off or to loose the connection, but if we succeeded, then it was really wonderful.

On the other hand, Sexual Trance like interactions much less risky.  We could have any flow of private thoughts so long as we remained in our sex bond, all was ok, focusing on sensational aspects.  Now, some overlapping seems to exist.  Seems there are always some elements of both Sexual Trance and Partner Engagement, as we may be connecting and engaging in the way we try to please the other and using non verbal communication... .but I do recognize that when we felt insecure with each other or such, always felt safer to connect via Sexual Trance.  I do feel the level of non verbal communication is important for satisfying  trance sex, which sort of brings it a bit closer to Partner Engagement sex anyway.

Anyway, I think it is quite helpful to have Sexual Trance vs Partner Engagement on a continuum of some sort.  I do feel as my emotional growth has matured, with it came the ability to choose to incorporate more Partner Engagement type sex. I can definitely relate to this type of sex requiring me to be most honest and present with myself first, and then that connection of being present, available, and engaging, certainly causing a most satisfying connection, all while we also appreciate the sharing of the trance sensations together.  Makes a whole lot of sense to me.