this is about YOUR attitudes and YOUR problems.
mark gungor has some information you might be interested in.
i dont know that you can find it on line, but in his seminar "laugh your way to a better marriage" he talks about this kind of circle that works in a healthy marriage. the primary interest for a man in marriage is sex, and for a woman its the companionship and romance etc.
if you get the romance, you give the sex, and when you give the sex, he gives the romance. thats how its SUPPOSED to work.
when this breaks down however, it just gets eaiser and easier for you to feel and say "i dont want to have sex anymore". this is not about your husband, it is about you, and the only way to solve this problem is for you to know and confess that you have the issue, and you need to find a way to solve it. RIGHT NOW, look up counseling in your area. you need some marriage/family counseling, and if you are Christian i wouldnt take anything less than real, Christian counseling.
when you did "give in" was this once a month or less? how often were you "just doing it for him"? and yes, the frequency matters. just having sex once isnt going to solve the problem, but having it multiple times in closer frequency can help. believe it or not, sex for you is INCREDIBLY emotional, and i cant tell you the number of times i have cried after sex. it seems as if it would be a bad thing, but its not; those are your emotions clicking in. and somehow it seems you are afraid of that, or you think that somehow this is a bad sign. does he know you cry? does he comfort you? let him know, let him comfort you! this is a bonding emotional experience, which is why people like mark gungor say no one should ever have sex outside of marriage; for the woman, it is like emotional bonding glue!
ps. even if you have not been sexually abused, it is likely that many people have been emotionally abused. there are various different ways that people are emotionally abused, but examine your relationship with your parents, and especially your father. was it distant? was it confusing? complicated? was it close? or not? think about things like that too, because whether you realize it or not, you can transfer emotions/feelings/experiences with your father/family to your marriage.
one thing i would suggest is to have sex at a higher frequency. yes, you are going to feel like you are forcing yourself. but it might help reignite things for you. every night for a week. i mean, its just a week right? get some lube if you need it, and dont forget (this is VERY important) to tell him what you like!! if you need some foreplay, ask for it! a massage, a bubble bath, a weekend in a hotel with all of the above, an adult board game (like 'an enchanted evening') or even those silly dice with different actions and different body parts on it. take your time. tell him exactly what you need, where you want to be touched, or touch yourself! nothing makes a man happier than you being happy, even if you are doing some of the work!
by the way, are you sexual at all? i mean, do you have "private time" ? if yes, i suggest NOT doing that AT ALL. this will help redirect your needs to your husband and only your husband, not your hand, or a toy or something.
if you do not, and arent interested, have you considered a hormonal imbalance? this is a really simple thing to fix. i mean, all this drama, all this frustration could simply be the work of some hormonal imbalance that can easily be fixed through your doctor. make an apointment NOW with your docctor and see if there isnt some sort of problem there. bring your husband with you, this will help you to be able to have his views and also to let him know what your doctor says. its like having him there to support you which is how it should be.
dont keep your husband at arms length. do things with him. lay in bed at night just talking (and yes, you can get him to agree to just talking LOL). find out other things your husband is thinking, feeling.
anyway, make a doc's appt, find counseling (your doctor might be able to refer you), have sex every day for a week, let your husband comfort you if you feel like crying, relax that the crying is an emotional reaction, not necessarily a sign something is wrong. it almost seems like you want to shut down, like theres no spark. revisit some of your old haunts from when you were dating, do things you used to do back them, even if its necking in the car or something! but this CAN be fixed, and it SHOULD be fixed. your husband wants this. your family deserves this. YOU deserve this.