Hi. There can be a strong Plutonian theme in a relationship where neither person in out of control - it depends on the individuals.
And with regard to the person with more natal aspects to Pluto being more affected, that also depends - if they natally have personal planets contacting their Pluto, then they will be familiar with Pluto, and they will have probably experienced many relationships of all kinds, beginning at birth, where their Pluto was contacted along with these personal planets. This person might be struggling to express Pluto creatively, but it probably be nothing new.
A person whose Pluto is not integrated well with the rest of their natal chart, especially if they have a chart which has a predominance of 'Plutonian' values and tendencies, will not be so familiar with Pluto, and may have had relationships in the past which don't contact Pluto very much. This person may have quite a shock when a relationship arouses their Pluto from its slumber! This would usually happen along with a Pluto-related transit of progression.
It sounds like you might fit into the 2nd paragraph even though you have Moon trine Pluto, you say. Is it a wide aspect, or is the Moon in sign that doesn't get on with Pluto, or have other parts of your natal chart tended to shut Pluto out in the past?
Venus Pluto would seem to be a very strong theme in the relationship from the aspects you mentioned in the synastry and composite. So the two Arroyo quotes potentially apply to both of you and might come out more through Venus issues: values, beautification, harmonisation, artistic taste and endeavour, the sensual and erotic side of sex, self-worth, resources, talents, etc.
Its interesting that you try hard to be polite to one another after an argument - as though your Venus's are trying extra hard to keep the less civilised Pluto energy at bay, perhaps?
If this is the first relationship that has felt so compulsive, it could be that you are someone who has tended to adapt to life through thinking rather than feeling. Its important to value all of the feelings that come up for you, but also of course to refrain from acting them out compulsively. It could be a deeply transformative relationship. When the intense feelings come up for you, maybe try separating the feeling from him - just feel it inside you. Observing non-judgementally is the key to working with difficult feelings. These feelings come from a deep and powerful place inside you - a vast reservoir of insight, passion and strength. But to tap into that reservoir creatively you may need to allow bits of yourself to be destroyed in Pluto's fire. It can feel very frightening to let these parts of us burn away without us trying to defend them, but they are no longer needed and need to be destroyed in order for us to be liberated and creative individuals. Rather than staying in the threatened part of you, try to be aware of it from another - the eye of the storm, as they say. From here it will be less frightening because you won't be so identified with the bit of you that needs to be destoyed by Pluto. There will still be uncomfortable feelings and body sensations, but you won't feel so much like you are fighting for your survival when things get heated.
Try not to control anything Venusian about one another - to try to control is to stay identified with, and in fierce defence of, the emotional baggage that you need to let go of.