I understand this is very difficult for you, alot of it is the views of the people that make having a sexual relation ship the same as porn or visa versa, I am not refering any of what I type to the odd or masticus or as such, only the every day living people not trying to make a point in life. I too have been looking at pictures of nude woman since about the same age as your guy and i am from before computers were around, I am thinking a lot of his views of it has to do with the human body and not so much as what people call porn, to me porn is something bad from what others have taught me to believe- is sex bad? , porn is what?-video tapes or dvd's of diffrent ways of having sex,,, I believe porn is nothing more than that, recorded video's of people having sex. Don't get me wrong though - being in a relation ship and for one of the partners to be looking at another woman or man can be horrible, the thought of them possibly being better than I, I have values and a way of life that does not need porn in my life. ,,,,,, It can seem more like you do not like sex, not that you don't, just that a guy does like a little spice some times,meaning a sexy dance or a little out rageous out fit can not only be a turn on but it gives a guy a feeling that- hay,I just don't think i will go on line tonight, I have every thing I need right here, a woman that loves me, she cares for my feelings, she understands how iam feeling, she is willing to do things with me that I don't need to look for else were.
The two of you can get through this togeather, so many are so quick to call somthing an addiction, Woman have morals and values and men are stuborn and relentless, is there a real diffrence between the man and woman? the woman does not want to become one of those (sluts), she controlls her fears of being one by controlling the amount and not letting things happen in bed that may look like on a video,hidding what she is doing only makes things worse - the other in a relation ship knows the other more better than we relize - noticing there is somthing up, whats wrong, usaly down deep and we don't even relize it our selves till some one points it out - , The guy needs to feel loved, his lady is attracted to him, she only wants him and feels so free with him but only with him, she does things that (exscuse the impression) those stuffy girls that think they are beyond sex, are not! A guy needs complete and undevided attention as only a woman wishes for too, guys do have trouble expressing them selves very well when reaching that moment, we are usaly the workers and can get very tired or winded and the feeling is so great, an out burst of feelings can be difficult when trying so hard to bring the woman to that moment, the thoughts of wanting to please her so, not to hear the screams of not real moments though, helping your self can help thing along so when that moment does occur, the two are more likly be there togeather. Being a guy and from having had a few relation ships I know about how a lot of sex happens when younger and it is difficult to talk about it with your guy or gal, it is so important to talk about sex with each other - not that he is more interested in videos or she forbids him from looking at other gals but to really talk about sex, when laying there and things start with a kiss and then a longer kiss - this is a perfect time to say somthing like - hun, you make me feel so good in side with your feelings of me or maybe somthing more in the movement as while having sex can do a lot too, A woman that just lays there and says things like o-ya but doesnt really express it with maybe her hands moving up or around his arms or aross his chest, even with out mid body movement from a gal can be a big turn off. In the first stages of the sex going slow is good but as things heat up, releasing inabitions is good.
The reason I am here is because I am having problems with a wounderful gal, she is such a sweet heart, she loves me more than any woman has or ever will. She knows I look at gals on line and knows I do not talk to them and has said it is ok but there is a look in her eyes that tells me other wise, I usaly only look at sites when it is that time of month when she doesn't want to do any thing but I have been told by woman groups that woman like to have more sex during this time and depending on what is happening there, some times we do but mostly don't, I have told her about what I learned and she admits it but not completly, only in her eyes and a sheepish look.
About being a addict - if we do it once or twise, we are curious - if we do it a few times, could be learning - if we do it several times we are labled an addict. I enjoy waking up in the mornings, having breakfast, feeding the horses and rabbits, seeing the smiles on my gals face or looks she gives me when I say somthing dumb but being serious then smile with her, I must be an addict too - waking up,breakfast,caring for the animals,my gals face expressions, bringing joy to my gal. Have you ever realy checked into as were porn (short for pornography) realy comes from, look at the people that start a drive on porn in an area, they are always bible thumpers, don't get any but maybe once or twice a month if at all any more - or are trying to make a name for them selves,,, don't get me wrong, I don't think a porn shop should be next to a school yard eaither but they do generaly have education to give as for personal; things in a couples own home and bed or some times some were in the house - ideas to help the other feel more better about them selves wanting to be more only with the other.
I am not perfect, we are all diffrent in some way but there are only 2 kinds of people on this earth - Men & Woman , That sure is a lot of addicts :O)
I wish the best for the two of you and remember most of all, one is the Lonleness number if you don't know what to do , two can be just as bad if you don't know what the other wants to do.
don't be blunt about the talks, be soft and with wispers will work the best.
If this helps, great, if not, I know it will help others.
Take care, you have a lot of life ahead of you and even though it seems to go so slow, it will pass by so fast, make the most of every moment, I am 43, not my fault i got older, I am the same person though.

So do you think that feelings of nausea, loss of appetite, loss of sleep and frequent bouts of depression are linked to his addiction and my unhappiness with it?

This is another sad and difficult situation, where you desperately want to help and keep your relationship and the hard fact is that only he can help himself.

It is hard to overcome any addiction, and almost everyone needs help. At his age is the best time to conquer it and you stand a good chance of success, but only he can decide to get the help he needs. A good starting off point would be the university counselling service, but that would only be the start.

At the same time, you need to start thinking of yourself and focussing on your own health and wellbeing. You are right that this relationship is making you ill just now, and you need to put your energy into your own future. Concentrate on other things, friends, studies, enjoying the sunshine and don't let his addiction blight your life.