If you can separate emotion from physicality then either you are not doing it right or you're a sociopath (or worse). The hormones that are summoned lay down the neural pathways and algorithms we associate with the emotional closeness, so even if you fake it, it is usually only until you make it (and why friends with benefits deals usually fall apart). Your reptile brain cannot differentiate between love as an emotion and love from orgasms as both flood your brain with dopamine. You can try and outsmart it, but the chicken and the egg thing will get you... and why we only have the single word 'love' for the physical act and for the emotion... they become one and the same.
Actually if you get really good at it then not only are the emotional and physical linked, but spirituality get involved as well and stuff really gets transcendent. But that is a so advanced that folks that even consider having "just a physical relationship" cannot even come near understanding because it goes so counter to such concepts.
So in summary I would say folks that are true to themselves wouldn't even consider such arrangements. Such 'enlightened relationships' are for the already damaged or for folks in denial that risk causing damage to themselves and their partner. It is not the natural state of the body and mind to try and separate physical and emotional love with your chosen mate, and if you insist on trying to fight nature, you will lose.