Dear OP, your partner has one redeeming feature, but unfortunately it does not make him someone you or any other woman should be with. The redeeming feature is that he is being honest enough to tell you not to have any changes to hair, make-up, etc, because he knows that that will not make any difference to how he feels and behaves.
You could be Miss UK, Miss World, or even Miss Universe (?), and it wouldn't make any difference, because he can not get or maintain an erection if he is not watching, or at least thinking about porn when trying to get aroused.
It doesn't sound like he has much time for a job, but if he does have one, he probably masterbates in a toilet cubicle at work, and if you knew about it, you would probably query how he can do that when he is not actually watching porn, the answer is that he can sit there with his eyes closed thinking about one of the many shoots he has watched, or (and sorry this one might hurt even more), he can imagine some female he has seen that day, and because he can't actually imagine what she looks like naked, or in the throes of sex, oo with her hands deep in soapy water washing the breakfast dishes, then he can fantasise anything he wants about her, maybe even just by putting her face onto one of the porn "stars" body.
He cannot do that with anyone who he knows intimately in real life, because as well as seeing them at their very best, which could be having Hollywood A star movie looks, he will have also seen them straight put of bed, with no make-up on, their hair not even brushed yet, and he will probably also have seen them with their hair scrapped back as they vomit into the toilet bowl, whether through illness, pregnancy or drunkeness, and he can no longer cope sexually with normality.
Your so called partner needs fantasy to get and keep an erection. If he could be transported into one of his pornographic sex shoot videos, he almost certainly could not get, or keep an erection (even with the help of someone who I think is called a "fluffer"). He would be unable to have an erection because once on set it is no longer a fantasy. There are cameras, strong lights, directors telling them and the female performers to suddenly stop, withdraw, don't cum yet - because they are not in the position the director wants them in for the cum shot...
Many, many couples can and do use porn as part of their sex lives, and if they watch it together - but only occassionally - both sexes can get some pleasurable enjoyment from it. If that builds up until the only time either of them, but I guess more frequently that it is the man, can get turned on and excited, is when they watch porn, then that sexual relationship has now failed. One or the other, but again I assume much more frequently its the woman who suffers from this, one of the partners (but I will call her, she), will start to feel used, unloved, unattractive, because her partner can no longer get an erection with her unless he is watching porn at the same time. It does not matter how pretty or sexy his partner looks, if she wants to make love in bed - or anywhere else, without porn on a screen, then it just isn"t going to happen.
You might never have watched porn with your "partner", or you might offer to have sex whilst watching porn, but if your partner has gone too far down the porn addiction line, he won't even be able to have sex with you under those circumstances - and you, well no woman, should agree to, or offer to, have sex under those conditions. That is because sooner or later (and it is extremely sad if it is a lot later, because the women may never be able to understand and regain the feelings of her own self worth, or at least not without a hell of a lot of counselling, sadness, hard bloody work, and a realisation of how much of their life they have wasted on a person who has probably gone past the point of no return, and would not even want to get over their addiction, if that was able to be offered to them on a plate), the porn addict's partner will start to feel just how you do now.
So please OP, stop thinking that his lack of attraction to you is anything to do with you, it really isn't. You are not a fantasy, you are a real life woman who sounds really pretty, and very loving, but who also drinks and pees, eats and poos, loves and needs love in return, you are you, and you are great just as you are, and he wouldn't have been with you in the first place if he had not been attracted to you. Please leave him as soon as possible, and please do what you need to do to relight your belief in yourself. I would give you a bunch of flowers, but there isn't one big enough.