That sucks PassionQT, me too. Get well!
Ultimatums don't work because you cannot make a person change what they want by demanding they do so.
I used to be far more insecure than I am now, I never really had a problem with porn, but I did feel like I had to compete with the "actresses" in the movies/magazines. I thought, "Obviously, if this is what you like to see, then this is what you are attracted to, and I do not fit into the parameters in any way shape or form. So why are you with me?". I felt like I was a substitute for what he REALLY wanted, and a poor one at that. I have grown a lot since that point and now watch a lot of porn myself. A LOT. It is essentially just and auditory and visual stimulant, designed to cater to fantasy, not reality. The things that I enjoy most in porn are those things that I won't likely ever do, and sometimes even things that freak me out a little. I do not expect that the man I am with will have the exact same views on pornography that I do, that is silly, his brain is not my brain. I do however expect that he/she will not let pornography interfere with our sex life, except to be beneficial.
Porn is not meant as a substitute for sex, it is meant as an aid in stimulation, the same as a mental fantasy, or the sensation created by a sex toy. I think that it is a great way to add variety to ones sex and fantasy life, without feeling the need to look elsewhere.