I'm not sure I worded this in the best way I could have, but here it is.
How many things do you do for people through out the day that you don't really want to do, or feel like doing at the time? Who are these people that you do these things for, friends, neighbors, in-laws, other drivers on the road? Do you ever ask your husband to change a light bulb, fix a leaky sink, mow the lawn, paint a room, rake the leaves, go to the store, make a phone call, do the taxes, clean out the garage, go to work...? Has he wanted to do each of these things every single time he has done them? Or has he done somethings that he didn't really want to do, but did them anyway because he loves and cares for his family? Have you ever not wanted to do something, clean something, get out of bed, go to a get together/party, exercise, eat something healthy, but then once you did, you liked it? A starving person is always going to be hungry.
When I got married, over 15 years ago, I was given a book. "The Act of Marriage; The Beauty of Sexual Love" by: Tim & Beverly LaHaye. This book is not 'gross'. They are very 'kind', for lack of a better word, with how they have written the book. I don't watch rated R movie, or many/most PG-13 movies, to give you an idea of where I'm coming from. Dr. Laura has some book out about loving and caring for your spouse if you like it more 'straight forward and to the point'.
I am SO glad that you are aware and concerned about this matter. I have heard that is all is well in the bedroom, then it's about 10% of your relationship, but if things are not going well in the bedroom, then it is 90% of the relationship. I thing I've worded that wrong, but I hope that you know what I mean. Everyone is different, but my mom would always tell me growing up, "If you don't use it, you loose it" and I don't see why it would not aply here too.
I hope this sounds caring and helpful, because that was my intent/meaning. I wish you all the best!