Psychology Today published this short article on the effects of pornography on the ability to commit to a relationship-
The conclusion was hard not to see coming: the more one views porn, the less committed one becomes to one's real-life mate-relationships. It has to do with sexual stimulation.
It is funny in a way, because I figured this one out years ago when I went on a pilgrimage for several weeks to Mt. Athos, where there were no women at all. I hadn't noticed it too much (being overwhelmed with all the other aspects of the trip) until I stepped off the ferry in Ouranopoli and walked out onto the dock. There were a dozen or so women there to pick up their husbands/boyfriends/male relatives, and... wow, it was a little unnerving.
Not having been around women for just a short time made us pilgrims notice them all the more. We laughed as we jumped into the taxi and headed off to a convent (a funny destination all things considered after this experience), but the effects subsided as we made several stops along the way and got used to being around women again.
The shock of that experience never left me. It was like coming out of a dark room into the sunlight. It took time to adjust.
When we bombard our senses with pornography, it is the exact opposite: it is like standing in the sunlight, then going indoors. We come in, and the whole world suddenly becomes dark and obscured.
I did say 'senses' because pornography is not just visual, but it is also perceived by what I call our 'socio-sexual sense.' This is, in my opinion, a real sense just as much as hearing and sight or taste. It does not have a single organ to rely on, just as our sense of temperature or kinesthesia. The Socio-Sexual Sense relates the person to other beings... animals and humans, male and female.
Just like other senses (the exception being smell), this sense is routed through the Limbic System of the brain, and gives us the ability to immediately react to situations as they come into perception. After all, we do not have to think long about sexual arousal... most of us can be instantly shocked by a sudden pornographic image that pops on the screen.
The Limbic System controls our reactions, and can flood the rest of the brain with chemicals which control behavior and the thinking of the higher Cerebrum.
So, when you are watching porn, the Limbic System is reacting to the senses of Vision and Socio Sexuality, then sending out the brain chemicals involved (this is a longer discussion). The Cerebrum is less involved in this process, and is largely switched 'off.' Otherwise, it would notice that the actors are not perfect or the video isn't clear.
But, the Limbic Brain doesn't notice these things. It thinks it is looking at a real woman, and then it sets about to convince the Cerebrum that this is real and it needs to act accordingly. The high levels of input become 'expected' by both brains. They adjust to the white-hot 'light' of porn (especially the HD variety), and so everything else becomes 'less.'
In mating relationships, the foundation is the Socio-Sexual sense, which discerns the relationship and defines the position of the self in relation to the other. If this sense has been overloaded by porn viewing, it is going to produce a 'duller image' to the rest of the brain, just like eyes adjusted to bright light produce a dimmer image in a regularly-lit room.
This study just confirms the effect, but we still have a long way to go to understand the role of the sense in relationships.